Publishing type：Research paper (scientific journal)   Publisher：Scientific Scholar  

Background:

Vagal nerve stimulation (VNS) is a palliative treatment for refractory epilepsy and intraoperative nerve stimulation is applied to the vagal and other nerves to prevent electrode misplacement. We evaluated these thresholds to establish intraoperative monitoring procedures for VNS surgery.

Methods:

Forty-six patients who underwent intraoperative nerve stimulation during VNS placement were enrolled. The vagal nerve and other exposed nerves were electrically stimulated during surgery, and muscle contraction was confirmed by electromyography of the vocal cords and visual recognition of cervical muscle contraction. The nerve thresholds and the most sensitive parts of the vagal nerve were analyzed retrospectively.

Results:

The stimulation of vagal nerves induced vocal cord responses in all 46 patients; the median thresholds of the most sensitive parts and all parts were 0.2 mA (range: 0.05–0.75 mA) and 0.25 mA (range: 0.15–1.5 mA), respectively. The medial middle region was identified as the most sensitive part of the vagal nerve in the majority of participants (82.5%). In 11 patients, other cervical nerves were stimulated and sternohyoid muscle contraction was induced with a median threshold of 0.35 mA (range: 0.1–0.7 mA) in eight patients, while sternocleidomastoid muscle contraction was induced with a median threshold of 0.2 mA (range: 0.1–0.2 mA) in three.

Conclusion:

Intraoperative stimulation of vagal nerves induces vocal cord responses with locational variations, and the middle part stimulation could minimize the stimulus intensities. The nerves innervating the sternohyoid and sternocleidomastoid muscles may be exposed during the procedure. Knowledge of these characteristics will enhance the effectiveness of this technique in future applications.

Other Link： http://surgicalneurologyint.com/surgicalint-articles/intraoperative-nerve-stimulation-during-vagal-nerve-stimulator-placement/

DOI： 10.25259/sni_303_2023

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Language：Japanese   Publisher：(株)メディカ出版  

Ichushi

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Impaired reperfusion in ischemic brain disease is a condition that we are increasingly confronted with owing to recent advances in reperfusion therapy. In the present study, rat models of reperfusion were investigated to determine the causes of acute seizures using magnetic resonance imaging (MRI) and histopathological specimens. Rat models of bilateral common carotid artery ligation followed by reperfusion and complete occlusion were created. We compared the incidence of seizures, mortality within 24 h, MRI, and magnetic resonance spectroscopy (MRS) to evaluate ischemic or hemorrhagic changes and metabolites in the brain parenchyma. In addition, the histopathological specimens were compared with those observed on MRI. In multivariate analysis, the predictive factors of mortality were seizure (odds ratios (OR), 106.572), reperfusion or occlusion (OR, 0.056), and the apparent diffusion coefficient value of the striatum (OR, 0.396). The predictive factors of a convulsive seizure were reperfusion or occlusion (OR, 0.007) and the number of round-shaped hyposignals (RHS) on susceptibility-weighted imaging (SWI) (OR, 2.072). The incidence of convulsive seizures was significantly correlated with the number of RHS in the reperfusion model. RHS on SWI was confirmed pathologically as microbleeds in the extravasation of the brain parenchyma and was distributed around the hippocampus and cingulum bundle. MRS analysis showed that the N-acetyl aspartate level was significantly lower in the reperfusion group than in the occlusion group. In the reperfusion model, RHS on SWI was a risk factor for convulsive seizures. The location of the RHS also influenced the incidence of convulsive seizures.

DOI： 10.2176/jns-nmc.2022-0372

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The investigation of how to control the development and growth of cerebral aneurysms is important for the prevention of subarachnoid hemorrhage. Although there have been several types of research studies on computational fluid dynamics (CFD) analysis of brain aneurysm development and growth, there has been no unified interpretation of the CFD analysis results. The purpose of this study is to clarify the characteristics of CFD analysis results related to the development of cerebral aneurysms using an animal model. Nineteen rat models of cerebral aneurysms were created, and the CFD analysis results between the cerebral aneurysm group [n = 10; the aneurysm was observed on magnetic resonance angiography (MRA) within 10 weeks after aneurysm induction surgery] and the nonaneurysm group (n = 9) were compared. All aneurysms were confirmed on the proximal segment of the left cerebral artery (P1), and the cross-sectional area and curvature of the left P1 were evaluated together. In the cerebral aneurysm group, there was a decrease in wall shear stress (WSS) that is consistent with the location of the aneurysm compared to the nonaneurysm group. The cross-sectional area of the left P1 gradually increased in the aneurysm group but not in the nonaneurysm group. The mean curvature in the entire left P1 was higher in the aneurysm group than in the nonaneurysm group. This study revealed that the development of cerebral aneurysms is due to changes in vascular morphology, namely, an increase in vessel diameter and a high curvature, and a decreased WSS consistent with the site of aneurysm development using this animal model.

DOI： 10.2176/jns-nmc.2023-0005

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OBJECTIVE: Transcranial electrical stimulation motor evoked potentials (TES-MEP) are widely used to monitor motor function; however, broad current spread and induced body movement are limitations of this technique. We herein report a localized stimulation technique for TES-MEP that induces unilateral MEP responses. METHODS: The stimulation of C1(+)-C4(-) or C2(+)-C3(-) was performed to induce right- or left-sided muscle contraction, respectively, in 70 patients. Electromyography was recorded by placing electrodes on the bilateral abductor pollicis brevis (APB) and abductor hallucis (AH) muscles. Stimulation conditions were regulated in the range to induce unilateral muscle contractions contralateral to the anodal stimulation. The thresholds and amplitudes of TES-MEP were retrospectively analyzed. RESULTS: The thresholds of APB were lower than those of AH in 47 patients, AH thresholds were lower than those of APB in 6 patients, and both APB and AH started to respond at the same intensity in 15 patients. This technical stimulation induced contralateral limb contractions with a suprathreshold stimulation of 129.4 ± 35.6 mA (mean ± standard deviation) in 68 patients (97%). Amplitudes in the suprathreshold stimulation of APB and AH responses were 727.5 ± 695.7 and 403.3 ± 325.7 μV, respectively. CONCLUSIONS: The C1(+)-C4/C2(+)-C3(-) stimulation in TES-MEP enables a localized stimulation to induce unilateral MEP responses. SIGNIFICANCE: Our stimulation technique enables the stable and safe monitoring of unilateral limbs, and contributes to the reliable monitoring of motor function in neurosurgery.

DOI： 10.1016/j.clinph.2023.03.017

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PURPOSE: The present study evaluated the utility of the steady-state responses of cortico-cortical evoked potentials (SSCCEPs) and compared them with the responses of conventional CCEPs. METHODS: Eleven patients with medically intractable focal epilepsy who underwent the implantation of subdural electrodes or stereoelectroencephalography were enrolled. Conventional CCEPs were obtained by averaging responses to alternating 1-Hz electrical stimuli, and 5-Hz stimuli were delivered for recording SSCCEPs. The distribution of SSCCEPs was assessed by a frequency analysis of fast Fourier transform and compared with conventional CCEPs. RESULTS: Steady-state responses of cortico-cortical evoked potentials were successfully recorded in areas consistent with conventional CCEPs in all patients. However, SSCCEPs were more easily disturbed by the 5-Hz stimulation, and small responses had difficulty generating SSCCEPs. CONCLUSIONS: Steady-state responses of cortico-cortical evoked potentials may be a useful alternative to conventional CCEPs.

DOI： 10.1097/WNP.0000000000000887

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Language：Japanese   Publisher：(株)メディカ出版  

Ichushi

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Language：Japanese   Publisher：(一社)日本神経学会  

Ichushi

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OBJECTIVE: The present study investigated the networks of visual functional areas using electric brain stimulation (EBS) and diffusion tensor imaging (DTI). METHODS: Thirteen patients with intractable focal epilepsy in which visual functional areas were identified by EBS were enrolled. An electric stimulation at 50Hz was applied to electrodes during several tasks. DTI was used to identify subcortical fibers originating from the visual functional areas identified by EBS. RESULT: The electrical stimulation induced three types of visual symptoms: visual illusions (change of vision), visual hallucinations (appearance of a new object), and blurred vision. Visual illusions were associated with stimulation of lateral temporo-parieto-occipital areas, and visual hallucinations with stimulation of lateral/basal temporal areas, the occipital lobe and the precuneus. Stimulus intensities eliciting visual illusions were significantly higher than those for visual hallucinations. Tractography revealed that the superior fronto-occipital fasciculus was associated with visual illusions and the middle longitudinal fasciculus with visual hallucinations, and both symptoms shared several subcortical fibers such as the vertical occipital fasciculus, inferior fronto-occipital fasciculus, superior longitudinal fasciculus, inferior longitudinal fasciculus, optic radiations, and commissural fibers. CONCLUSION: The present study revealed the characteristic cortical regions and networks of visual functional areas. The results obtained provide information on human visual functions and are a practical guide for electrical cortical stimulation.

DOI： 10.1016/j.neurol.2022.12.011

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Intraoperative electrocorticography (iECoG) is widely performed to identify irritative zones in the cortex during brain surgery; however, several limitations (e.g., short recording times and the effects of general anesthesia) reduce its effectiveness. The present study aimed to evaluate the utility of iECoG for localizing epileptogenic zones. We compared the results of iECoG and chronic electrocorticography (cECoG) in 25 patients with refractory epilepsy. Subdural electrodes were implanted with iECoG under general anesthesia (2% sevoflurane). cECoG recordings were performed for 3-14 days. The distribution of iECoG spikes was compared with cECoG spike, seizure onset zone, and resection areas. The concordance patterns of each distribution were classified into four patterns: Group 1: No spike in iECoG, Group 2: concordant (2a: iECoG smaller, 2b: iECoG larger, Group 3: discordant >50%). The concordance rate of interictal spikes, seizure onset zones, and resection areas were 88.0% (Group 2a: 72.0%, Group 2b: 16.0%), 70.0% (Group 2a: 25.0%, Group 2b: 45.0%), and 81.0% (Group 2a: 42.9%, Group 2b: 38.1%), respectively. The resection of iECoG spike areas significantly correlated with good surgical outcomes. The indication and limitations of iECoG need to be realized, and the complementary use of iECoG and cECoG may enhance clinical utility.

DOI： 10.2176/jns-nmc.2022-0252

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OBJECTIVE: This study aimed to enable the automatic detection of the hippocampus and diagnose mesial temporal lobe epilepsy (MTLE) with the hippocampus as the epileptogenic area using artificial intelligence (AI). We compared the diagnostic accuracies of AI and neurosurgical physicians for MTLE with the hippocampus as the epileptogenic area. METHOD: In this study, we used an AI program to diagnose MTLE. The image sets were processed using a code written in Python 3.7.4. and analyzed using Open Computer Vision 4.5.1. The deep learning model, which was a fine-tuned VGG16 model, consisted of several layers. The diagnostic accuracies of AI and board-certified neurosurgeons were compared. RESULTS: AI detected the hippocampi automatically and diagnosed MTLE with the hippocampus as the epileptogenic area on both T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) images. The diagnostic accuracies of AI based on T2WI and FLAIR data were 99% and 89%, respectively, and those of neurosurgeons based on T2WI and FLAIR data were 94% and 95%, respectively. The diagnostic accuracy of AI was statistically higher than that of board-certified neurosurgeons based on T2WI data (p = 0.00129). CONCLUSION: The deep learning-based AI program is highly accurate and can diagnose MTLE better than some board-certified neurosurgeons. AI can maintain a certain level of output accuracy and can be a reliable assistant to doctors.

DOI： 10.1371/journal.pone.0282082

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Ichushi

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Language：English   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：English   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(株)メディカ出版  

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Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(株)メディカ出版  

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We evaluated the effect of early surgical intervention on the change in memory performance of patients with low-grade brain tumors associated with epilepsy. Twenty-three adult patients with low-grade brain tumors and epilepsy who underwent surgery at our institution between 2010 and 2019 were included. The Wechsler Memory Scale-Revised (WMS-R) was used to assess cognitive memory performance. Memory performance before and after surgery was retrospectively evaluated. In addition, the relationships among preoperative memory function, postoperative seizure outcome, preoperative seizure control, temporal lobe lesion, and change in memory function were examined. There were statistically significant improvements from median preoperative to postoperative WMS-R subscale scores for verbal memory, general memory, and delayed recall (p<0.001, p<0.001, and p=0.0055, respectively) regardless of preoperative sores and tumor location. Good postsurgical seizure control was associated with significant improvements in postoperative WMS-R performance. Our results indicated that early surgical intervention might improve postoperative memory function in patients with low-grade brain tumors and epilepsy.

DOI： 10.2176/jns-nmc.2021-0175

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Electrical cortical stimulation is widely performed and is the gold standard for functional mapping in intractable epilepsy patients; however, a standard protocol has not yet been established. With respect to stimulation methods, two techniques can be applied: monopolar and bipolar stimulation. We compared the threshold to induce clinical symptoms between these two stimulation techniques. Twenty patients with intractable epilepsy who underwent electrical cortical stimulation for functional mapping were retrospectively investigated. We evaluated the stimulation intensity thresholds required to induce motor, sensory, and language symptoms. A total of 114 electrodes in 20 patients were used to investigate motor, sensory, and language symptoms. The thresholds required to induce motor (median value, bipolar: 4 mA, monopolar: 5 mA, p < 0.05) and language symptoms (bipolar: 8 mA, monopolar: 10 mA, p < 0.0005) were significantly higher for monopolar stimulation than those for bipolar stimulation. However, for sensory symptoms, no significant differences were found in the required thresholds between monopolar and bipolar stimulation (bipolar: 4 mA, monopolar: 4 mA, p = 0.474). Bipolar cortical stimulation required lower intensities to produce clinical motor and language symptoms and thus would be safe and suitable for screening of the eloquent area in functional mapping.

DOI： 10.2176/jns-nmc.2021-0389

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The aim of the present study was to evaluate motor area mapping using functional magnetic resonance imaging (fMRI) compared with electrical cortical stimulation (ECS). Motor mapping with fMRI and ECS were retrospectively compared in seven patients with refractory epilepsy in which the primary motor (M1) areas were identified by fMRI and ECS mapping between 2012 and 2019. A right finger tapping task was used for fMRI motor mapping. Blood oxygen level-dependent activation was detected in the left precentral gyrus (PreCG)/postcentral gyrus (PostCG) along the "hand knob" of the central sulcus in all seven patients. Bilateral supplementary motor areas (SMAs) were also activated (n = 6), and the cerebellar hemisphere showed activation on the right side (n = 3) and bilateral side (n = 4). Furthermore, the premotor area (PM) and posterior parietal cortex (PPC) were also activated on the left side (n = 1) and bilateral sides (n = 2). The M1 and sensory area (S1) detected by ECS included fMRI-activated PreCG/PostCG areas with broader extent. This study showed that fMRI motor mapping was locationally well correlated to the activation of M1/S1 by ECS, but the spatial extent was not concordant. In addition, the involvement of SMA, PM/PPC, and the cerebellum in simple voluntary movement was also suggested. Combination analysis of fMRI and ECS motor mapping contributes to precise localization of M1/S1.

DOI： 10.2176/jns-nmc.2021-0247

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Ichushi

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Language：Japanese   Publisher：(一社)日本小児神経学会  

Ichushi

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Language：Japanese   Publisher：(株)中外医学社  

Ichushi

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Language：Japanese   Publisher：(株)メディカ出版  

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：日本生体磁気学会  

Ichushi

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Language：English  

DOI： 10.3389/fneur.2022.1056301

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OBJECTIVE: The present study investigated the cortical areas and networks responsible for hyperkinetic seizures by analyzing invasive recordings and diffusion tensor imaging (DTI) tractography. METHODS: Seven patients with intractable focal epilepsy in whom hyperkinetic seizures were recorded during an invasive evaluation at Sapporo Medical University between January 2012 and March 2020 were enrolled in the present study. Intracranial recordings were analyzed to localize seizure-onset zones (SOZs) and symptomatogenic zones (spread areas at clinical onset). DTI was used to identify the subcortical fibers originating from SOZs. RESULTS: Ten SOZs were located in four areas: (1) the inferior parietal lobule (two SOZs in two patients), (2) temporo-occipital junction (three SOZs in two patients), (3) medial temporal area (three SOZs in three patients) and (4) medial/lateral frontal lobe (two SOZs in two patients). Symptomatogenic zones appeared to be the premotor area, basal temporal area, temporo-occipital junction, and the postcentral gyrus/supramarginal gyrus. The tractographic analysis revealed that the inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF), middle longitudinal fasciculus (MLF), arcuate fasciculus (AF)/superior longitudinal fasciculus (SLF) II, III, and cingulum bundle may be associated with hyperkinetic seizures. CONCLUSION: The present results suggest the cortical areas (the inferior parietal lobule, temporo-occipital junction, medial temporal area, and medial/lateral frontal lobe) and subcortical fibers (IFOF, ILF, MLF, AF/SLFII, III, and the cingulum bundle) responsible for generating hyperkinetic seizures.

DOI： 10.1016/j.yebeh.2021.108405

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Ichushi

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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OBJECTIVE: The present study investigated the effects of the stimulus polarity and location of motor evoked potential (MEP) to establish a stimulation protocol. METHODS: Nineteen patients who intraoperatively underwent MEP in bipolar direct cortical stimulation were enrolled in the present study. Somatosensory evoked potentials (SEP) of the contralateral median nerve stimulation were recorded to determine stimulation sites. MEP was performed under two settings in all patients: 1. Anodal bipolar stimulation: an anode on the precentral gyrus and a cathode on the postcentral gyrus, 2. Cathodal bipolar stimulation: a cathode on the precentral gyrus and an anode on the postcentral gyrus. MEP amplitudes and the coefficient of variation (CV) at a stimulation intensity of 25 mA and the thresholds of induced MEP were compared between the two settings. RESULTS: An electrical stimulation at 25 mA induced a significantly higher amplitude in cathodal bipolar stimulation than in anodal bipolar stimulation. Cathodal bipolar stimulation also showed significantly lower thresholds than anodal stimulation. CV did not significantly differ between the two groups. CONCLUSIONS: These results indicate that cathodal bipolar stimulation is superior to anodal bipolar stimulation for intraoperative MEP monitoring. SIGNIFICANCE: MEP in cathodal bipolar cortical stimulation may be used in a safe and useful evaluation method of motor fiber damage that combines sensitivity and specificity.

DOI： 10.1016/j.clinph.2021.06.032

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

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While the bilateral common carotid artery (CCA) ligation model is widely used in cerebrovascular disease and dementia studies, it can frequently cause seizures. We examined the validity of seizure as an experimental model of ischemia. Eight-week-old male Wistar and Sprague-Dawley (SD) rats were implanted with electrocorticography (ECoG) electrodes and bilateral CCA ligation was performed and compared to the sham groups. ECoG monitoring was used to confirm the seizure discharge and count the number of spikes in the interictal phase 2 h after ligation, followed by power spectral analysis. Magnetic resonance imaging (MRI) was performed 6 h after bilateral CCA ligation to assess fractional anisotropy (FA), apparent diffusion coefficient (ADC), and cerebral blood flow (CBF) values. Magnetic resonance spectroscopy (MRS) was also performed and the ischemic parameters and electrophysiological changes were compared. The Wistar rat group had significantly higher mortality, frequency of seizures, incidence of non-convulsive seizures, and number of spikes in the interictal period compared to those in the SD rat group. Power spectral analysis showed increased power in the delta band in both Wistar and SD rat groups. MRI, after CCA ligation, showed significantly lower ADC values, lower glutamine and glutamate levels, and higher lactate values in Wistar rats, although there was no difference in FA values. Metabolic and electrophysiological changes after CCA ligation differed according to the rat strain. Wistar rats were prone to increased lactate and decreased glutamine and glutamate levels and the development of status epilepticus. Seizures can affect the results of ischemic experiments.

DOI： 10.2176/nmc.oa.2020-0365

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Language：Japanese   Publisher：(株)メディカ出版  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2021&ichushi_jid=J03120&link_issn=&doc_id=20210513160017&doc_link_id=%2Fao7nsgse%2F2021%2F003103%2F019%2F0478-0485%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fao7nsgse%2F2021%2F003103%2F019%2F0478-0485%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Ichushi

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An 11-year-old male patient developed weakness or right arm elevation after sudden movement at the age of eight. Reflex epilepsy was initially suspected; however, magnetic resonance imaging and electroencephalography (EEG) revealed no abnormality. Video-EEG monitoring was performed, but no change was noted during attacks of weakness. He was diagnosed with paroxysmal kinesigenic dyskinesia (PKD) and carbamazepine has stopped his attacks. PKD is a rare neurological disorder characterized by brief attacks of involuntary movement triggered by sudden voluntary movements, which may be confused with reflex epilepsy. PKD should be considered as a differential diagnosis of reflex epilepsy.

DOI： 10.18999/nagjms.83.2.361

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Language：Japanese   Publisher：(公社)日本臨床工学技士会  

Ichushi

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This study investigated the networks originating from frontal eye fields (FEFs) using electric cortical stimulation and diffusion tensor imaging (DTI). Seven patients with intractable focal epilepsy, in which FEFs were identified by electrical cortical stimulation, were enrolled in this study. Electric stimulation at 50 Hz was applied to the electrodes for functional mapping. DTI was used to identify the subcortical fibers originating from the FEFs with two regions of interests (ROIs) in the FEF and contralateral paramedian pontine reticular formation (PPRF). FEFs were found in the superior precentral sulcus (pre-CS) in six patients and superior frontal gyrus (SFG) in three patients. DTI detected fibers connecting FEFs and contralateral PPRFs, passing within the internal capsule. The fibers were located close to the lateral antero-superior border of the subthalamic nucleus (STN) and medial posterior border of the globus pallidus internus (GPi). This study found the characteristic subcortical networks of the FEF. These tracts should be noted to prevent complications of deep brain stimulation (DBS) of the STN or GPi.

DOI： 10.2176/nmc.oa.2020-0306

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Language：Japanese   Publisher：Movement Disorder Society of Japan (MDSJ)  

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Awake craniotomy has been widely performed in patients with glioma in eloquent areas to minimize postoperative brain dysfunction. However, neurological examination in awake craniotomy is sometimes problematic due to communication difficulties during the intraoperative awake period. We evaluated preoperative predictors of these difficulties in awake craniotomy for patients with glioma. In all, 136 patients with glioma who underwent awake craniotomy at our institution between January 2012 and January 2020 were retrospectively evaluated. Patients were divided into two groups (appropriately awake group and inappropriately awake group) depending on their state during the intraoperative awake period, and the relationship between communication difficulties in awake craniotomy and both clinical and radiological characteristics were assessed. The appropriately awake group included 110 patients, and the inappropriately awake group included 26 patients. Reasons for inclusion in the inappropriately awake group were insufficient wakefulness in 15 patients, restless state in 6, and intraoperative seizures in 5. In multivariate analysis, the likelihood of being inappropriately awake was inversely correlated with preoperative seizures (odds ratio [OR], 0.23; 95% confidence interval [CI], 0.06-0.89; p = 0.033) and positively correlated with left-sided lesions (OR, 7.31; 95% CI, 1.54-34.62; p = 0.012). Both lack of preoperative seizures and left-sided lesions were identified as risk factors for intraoperative difficulties in awake craniotomy for patients with glioma. Understanding these risk factors may lead to more appropriate determination of eligibility for awake craniotomy.

DOI： 10.2176/nmc.oa.2020-0232

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Language：Japanese   Publisher：(一社)日本神経学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVES: Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass operation is an effective treatment for patients with Moyamoya disease, and the hemodynamic parameters are reported to be improved after operation. However, there is no report concerning hemodynamic changes from the viewpoint of the preoperative anatomical structure of grafts. In this study, we evaluated the correlation between the preoperatively estimated blood flow of the graft obtained through image-based computational fluid dynamics (CFD) analysis and the hemodynamic changes in the acute phase after revascularization. MATERIALS AND METHODS: A total of 30 hemispheric sides of 23 patients were examined. The blood flow, that is, flow rate (FR) of the STA branches that were anastomosed to the MCA was evaluated using CFD analysis based on computed tomography (CT) angiography imaging data. The correlations between the FR and the hemodynamic changes in the acute phase after revascularization obtained through CT perfusion were assessed. RESULTS: The preoperatively estimated FR of the graft was moderately correlated with the changes in the mean transit time significantly and weakly correlated with those in the cerebral blood flow and cerebral blood volume. In addition, the FR was strongly correlated with age and the diameter of the STA from the origin to the bifurcation. CONCLUSION: The preoperatively estimated FR of the graft obtained through image-based CFD analysis contributed to the improvement of the mean transit time after revascularization. Because the FR of the graft was associated with the diameter of the STA, the size of the STA might be an important factor in postoperative hemodynamic changes. This might lead to the risk assessment of acute drastic hemodynamic changes as cerebral hyperperfusion, and consequently, better surgical outcomes might be expected.

DOI： 10.1016/j.jstrokecerebrovasdis.2020.105450

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Several structures including subthalamic nucleus (STN), the caudal zona incerta (cZI), the prelemniscal radiation (Raprl), and the thalamic ventral intermediate nucleus (Vim) have been reported to be useful for improving symptoms of Parkinson's disease (PD). However, the effect of each target is still unclear. Therefore, we investigated each structure's effects and adverse effects using a directional lead implanted in the posterior STN adjacent to the cZI and Raprl in two patients with tremor-dominant PD. In Case 1, maximal reduction of tremor was obtained by stimulation toward the Vim, and stimulation toward the thalamic reticular nucleus (TRN) reduced verbal fluency, but did not induce dysarthria. In Case 2, maximal reduction of tremor was obtained by stimulation toward the dorsal STN and Raprl. Maximal reduction of rigidity was achieved by stimulation toward the dorsal STN, Raprl, and cZI. Bradykiensia was improved by stimulation in all directions, but dyskinesia and dysarthria were evoked by stimulation toward the dorsal STN and cZI. The directional lead may elucidate the stimulation effect of each structure and broaden target selection depending on patients' symptoms and adverse effects.

DOI： 10.2176/nmc.tn.2020-0210

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Language：Japanese   Publisher：(一社)日本定位・機能神経外科学会  

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BACKGROUND: Deep brain stimulation is an effective treatment for severe tremor in essential tremor and Parkinson disease (PD). However, progressive loss of the beneficial effects of deep brain stimulation may occur due to several factors. CASE DESCRIPTION: We assessed the effects of different temporal patterns of cycling stimulation in the posterior subthalamic area, subthalamic nucleus, and the ventral intermediate nucleus of the thalamus in 3 PD patients with early decline of tremor suppression associated with severe tremor rebound. CONCLUSIONS: Certain temporal patterns of cycling (10 seconds on/1 second off or 30 seconds on/5 seconds off, soft start off) were useful for treating tremor habituation and rebound and showed long-term tremor suppression. Cycling stimulation may prevent tremor habituation in PD patients with severe tremor rebound.

DOI： 10.1016/j.wneu.2020.08.141

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Language：Japanese   Publisher：日本てんかん学会-北海道地方会  

Ichushi

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Language：Japanese   Publisher：(一社)日本神経学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本小児神経外科学会  

Ichushi

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INTRODUCTION: This study investigated the networks of Negative motor areas (NMAs) using electric cortical stimulation and diffusion tensor imaging (DTI). METHODS: Twelve patients with intractable focal epilepsy, in which NMAs were identified by electrical cortical stimulation, were enrolled in this study. Electric stimulation at 50Hz was applied to the electrodes during motor tasks to identify the NMAs. DTI was used to identify the subcortical fibers originating from the NMAs found by electrical stimulation. RESULTS: NMAs were found in lateral frontal areas (premotor area (PM) and precentral gyrus) in all 12 patients, in pre-supplementary motor areas (pre-SMAs) in four patients, and in posterior parietal cortices (PPCs) in four. DTI detected fibers connecting to the ipsilateral PMs, PPCs and temporal regions via U-fibers, superior longitudinal fasciculus (SLF), and arcuate fasciculus (AF) from the lateral frontal NMAs. Pre-SMA-NMAs had connections with ipsilateral PMs and contralateral pre-SMAs via the frontal aslant tract and transcallosal commissural fibers, and PPC-NMAs with ipsilateral PMs via SLF and AF. CONCLUSION: This study found the characteristic cortical network of each NMA, and especially revealed new insight of pre-SMA-NMA and PPC NMA. These NMAs might be associated with different mechanism of negative motor response.

DOI： 10.1016/j.neurol.2019.12.005

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OBJECTIVE: The aim of the present study was to compare localization of the language cortex using electrical cortical stimulation (ECS) and functional magnetic resonance imaging (fMRI) to establish the relevance of fMRI language mapping. METHODS: Language mapping with fMRI and functional ECS mapping were retrospectively compared in ten patients with refractory epilepsy who underwent fMRI language mapping and functional ECS mapping between June 2012 and April 2019. A shiritori task, a popular Japanese word chain game, was used for fMRI language mapping. RESULTS: BOLD signal activation was observed in the left inferior frontal gyrus (including the pars opecularis and the pars triangularis), and superior temporal gyrus, which is a language-related area, as well as in the left superior and middle frontal gyri, the intraparietal sulcus, and fusiform gyrus. These results were compared with ECS to elucidate the functional role of the activated areas during fMRI language tasks. These activated areas included language areas, negative motor areas, supplementary motor areas (SMAs), and non-functional areas. CONCLUSION: The activated areas of fMRI language mapping include language-related areas, the negative motor area, and SMAs. These findings suggest the involvement of language and higher order motor networks in verbal expression.

DOI： 10.1016/j.jocn.2020.05.007

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OBJECTIVES: Balloon test occlusion (BTO) is performed to evaluate ischemic tolerance for large and giant cerebral aneurysms and head and neck tumors that may require parent artery occlusion. However, ischemic tolerance for the temporary test occlusion does not always guarantee a tolerance for permanent occlusion. In this study, we evaluated the utility of computed tomography (CT) perfusion during BTO to quantify ischemic tolerance for detecting delayed ischemic stroke. MATERIALS AND METHODS: Forty-one patients who underwent BTO for the internal carotid artery were included. The correlations between the parameters of CT perfusion and collateral angiographic appearance or stump pressure during BTO were evaluated. The cerebral blood flow (CBF), cerebral blood volume, mean transit time (MTT), and time to peak (TTP) were obtained through CT perfusion, and the asymmetry ratios were determined. Collateral angiographic appearances were categorized into 5 grades (0-4). RESULTS: The collateral angiographic appearance showed moderate correlations with CBF, MTT, and TTP that was significant. Of these, the absolute value of the correlation coefficient was the highest for MTT. MTT also showed a moderate correlation with stump pressure. CBF and MTT were significantly different between the poor collateral group (grades 2 and 3) and the good collateral group (grade 4). Based on the MTT, the good collateral group was identified with high sensitivity (75.0%) and specificity (81.2%). CONCLUSIONS: In BTO, the MTT obtained through CT perfusion showed a correlation with collateral angiographic appearance and stump pressure. Thus, the MTT might be useful to quantify ischemic tolerance for detecting delayed ischemic stroke.

DOI： 10.1016/j.jstrokecerebrovasdis.2020.104807

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The purpose of this study was to investigate whether and how vagus nerve stimulation (VNS) reduces the epileptogenic activity in the bilateral cerebral cortex in patients with intractable epilepsy. We analyzed the electrocorticograms (ECoGs) of five patients who underwent callosotomy due to intractable epilepsy even after VNS implantation. We recorded ECoGs and analyzed power spectrum in both VNS OFF and ON phases. We counted the number of spikes and electrodes with epileptic spikes, distinguishing unilaterally and bilaterally hemispherically spread spikes as synchronousness of the epileptic spikes in both VNS OFF and ON phases. There were 24.80 ± 35.55 and 7.20 ± 9.93 unilaterally spread spikes in the VNS OFF and ON phases, respectively (P = 0.157), and 35.8 ± 29.21 and 10.6 ± 13.50 bilaterally spread spikes in the VNS OFF and ON phases, respectively (P = 0.027). The number of electrodes with unilaterally and bilaterally spread spikes in the VNS OFF and ON phases was 3.84 ± 2.13 and 3.59 ± 1.82 (P = 0.415), and 8.20 ± 3.56 and 6.89 ± 2.89 (P = 0.026), respectively. The ECoG background power spectra recordings in the VNS OFF and ON phases were also analyzed. The spectral power tended to be greater in the high-frequency band at VNS ON phase than OFF phase. This study showed the reduction of epileptogenic spikes and spread areas of the spikes by VNS as immediate effects, electrophysiologically.

DOI： 10.2176/nmc.oa.2019-0221

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Although deep brain stimulation (DBS) is an established treatment for Parkinson's disease, the long-term suppression of tremor is still a challenging issue. We report two patients with tremor-dominant Parkinson's disease (PD) treated with unilateral thalamotomy of the ventralis intermedius nucleus (Vim) combined with the subthalamic nucleus (STN)-DBS or the posterior subthalamic area (PSA)-DBS. One year after the surgery, thalamotomy of the area from the Vim to the PSA showed improvement not only in tremor but also in rigidity and akinesia. PSA- or STN-DBS with low intensity stimulation eliminated residual PD symptoms. Combined DBS and thalamotomy may provide long-term improvement of the majority of PD symptoms using lower therapeutic stimulation voltages.

DOI： 10.1016/j.jocn.2020.02.014

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OBJECTIVES: Parkinson's disease (PD) is a neurodegenerative disease presenting characteristic motor features. Severity is usually assessed by clinical symptoms; however, few objective indicators are available. In this study, we evaluated the utility of dopamine transporter (DAT) imaging and subthalamic nucleus (STN) activities as indicators of PD severity. MATERIALS AND METHODS: Twelve hemispheres of ten patients with PD who underwent deep brain stimulation (DBS) were included in this study. Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part 3 scores were used to evaluate clinical severity. The relationship between specific binding ratio (SBR) of DAT imaging and the root mean square (RMS) of STN micro-electrode recording (MER) was evaluated. RESULTS: A negative correlation was detected between the MDS-UPDRS part 3 scores and SBR (N = 20, R2 = 0.418; P = 0.002). With respect to subscores, rigidity (R2 = 0.582; P < 0.001) and bradykinesia (R2 = 0.378; P = 0.004) showed negative correlation with SBR, whereas tremor showed no correlation (R2 = 0.054; P = 0.324) (N = 20). On the other hand, no correlation was found between MER and the MDS-UPDRS part 3 scores in ten hemispheres of six patients. CONCLUSION: DAT findings may be useful in evaluating PD severity, especially rigidity and bradykinesia.

DOI： 10.1016/j.jocn.2020.02.006

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Diffuse astrocytic and oligodendroglial tumors are frequently associated with symptomatic epilepsy, and predictive seizure control is important for the improvement of patient quality of life. To elucidate the factors related to drug resistance of brain tumor-associated epilepsy from a pathological perspective. From January 2012 to October 2017, 36 patients diagnosed with diffuse astrocytic or oligodendroglial tumors were included. Assessment for seizure control was performed according to the Engel classification of seizures. Patient clinical, radiological, and pathological data were stratified based on the following 16 variables: age, sex, location of tumor, existence of the preoperative seizure, extent of resection, administration of temozolomide, radiation therapy, recurrence, Karnofsky performance scale, isocitrate dehydrogenase 1, 1p/19q co-deletion, Olig2, platelet-derived growth factor receptor alpha, p53, ATRX, and Ki67. These factors were compared between the well-controlled group and drug-resistant seizure group. Twenty-seven patients experienced seizures; of these, 14 cases were well-controlled, and 13 cases were drug-resistant. Neither clinical nor radiological characteristics were significantly different between these two groups, though p53 immunodetection levels were significantly higher, and the frequency of 1p/19q co-deletion was significantly lower in the group with drug-resistant seizures than in the well-controlled group. In the multivariate analysis, only one item was selected according to stepwise methods, and a significant difference was observed for p53 (OR, 21.600; 95% CI, 2.135-218.579; P = 0.009). Upregulation of p53 may be a molecular mechanism underlying drug resistant epilepsy associated with diffuse astrocytic and oligodendroglial tumors.

DOI： 10.2176/nmc.oa.2019-0218

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Language：Japanese   Publisher：(一社)日本神経学会  

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Numerous non-epileptic physiological electroencephalographic (EEG) patterns morphologically mimic epileptiform activity. However, misleading non-epileptic findings of electrocorticography (ECoG) have not yet been examined in detail. The aim of the present study was to identify non-epileptic epileptiform ECoG findings. We retrospectively reviewed the intracranial recordings of 21 patients with intractable focal epilepsy who became seizure-free after a presurgical evaluation with subdural electrodes following resective surgeries at Sapporo Medical University between January 2014 and December 2018. Morphological epileptiform findings outside epileptogenic areas were judged as non-epileptic and analyzed. Seventeen areas in nine patients exhibited non-epileptic epileptiform activities. These areas were identified in the lateral temporal cortices, basal temporal areas, rolandic areas, and frontal lobe. Morphological patterns were classified into three types: 1) spiky oscillations, 2) isolated spiky activity, and 3) isolated fast activity. The normal cortex may exhibit non-epileptic epileptiform activities. These activities need to be carefully differentiated from real epileptic abnormalities to prevent the mislocalization of epileptogenic areas.

DOI： 10.1016/j.jocn.2019.08.094

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OBJECTIVES: To evaluate the effects of nonadherence to antiseizure medications (ASMs) and clinical characteristics on seizure control, we employed a prospective cohort cross-sectional study using self-reports and medical records of patients with epilepsy (PWEs). METHODS: Eight hundred and fifty-five PWEs taking ASMs were enrolled from fourteen collaborative outpatient clinics from January 2018 to March 2019. Questions from the Morisky Medication Adherence Scale were used as adherence self-reports. If a PWE's questionnaire indicated that they had missed doses of their ASMs, outpatient physicians asked them directly about the details of their compliance, including the timing of intentionally or unintentionally missed doses. The association between lack of seizure control and utilization outcomes, such as missed doses, demographics, and clinical characteristics of the PWEs, were assessed by univariate and multivariate analyses. RESULTS: Multivariate analysis revealed that forgetting to take ASMs was associated with lack of seizure control and the existence of focal to bilateral tonic-clonic seizures. Dementia, younger age, use of three or more antiepileptic agents, and living in a one-person household were associated with the risk of forgetting to take ASMs. SIGNIFICANCE: For PWEs with poor drug management or a high incidence of missed doses of ASMs, efforts to improve adherence could facilitate better seizure control and decrease focal to bilateral tonic-clonic propagation.

DOI： 10.1371/journal.pone.0240082

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Language：Japanese   Publisher：(一社)日本定位・機能神経外科学会  

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Epileptic nystagmus is a quick, repetitive, jerky movement of the eyeball caused by seizure activity, which is unaccompanied by other ictal phenomena. We report a case of moyamoya disease with epileptic nystagmus. A 23-year-old woman presented with a headache and transient hemiparesis on her left side. Magnetic resonance imaging showed no ischemic or hemorrhagic stroke lesions. Digital subtraction angiography confirmed stenosis of the terminal portion of the right internal carotid artery and the formation of moyamoya vessels on the right side. 123I-N-isopropyl-iodoamphetamine (123I-IMP) single photon emission computed tomography (SPECT) showed decreased uptake in the right basal ganglia, frontal, and parietal regions. After electroencephalography (EEG) and a hyperventilation test were performed, nystagmus appeared and was accompanied with a declining level of consciousness. Ictal EEG during an attack showed no epileptiform discharge. Moreover, the patient sometimes experienced simultaneous upper limb-shaking and gelastic attacks. After superficial temporal artery to middle cerebral artery bypass surgery was performed on the right side, symptom frequency and duration gradually decreased. Decreased 123I-IMP SPECT blood flow in the right frontal region is considered a mechanism that causes the onset of epileptic nystagmus. It is presumed that the attack was caused by an ischemic abnormality in the saccade region of the frontal eye field. Moreover, revascularization can effectively treat the symptoms of moyamoya disease.

DOI： 10.1016/j.jocn.2019.08.069

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Language：Japanese   Publisher：日本てんかん学会-北海道地方会  

Ichushi

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Language：Japanese   Publisher：(一社)日本定位・機能神経外科学会  

Ichushi

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Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: Vagus nerve stimulation is a palliative treatment for patients with refractory epilepsy; however, the misplacement of electrodes may cause complications and thus needs to be avoided. METHODS: We herein report an intraoperative monitoring technique to prevent the misplacement of electrodes. Endotracheal tube electrodes were inserted to record electromyographic activity from the vocal cords and identify the vagus nerve. Electromyography electrodes were placed on the sternomastoid muscle, sternohyoid muscle, geniohyoid muscle, and trapezius muscle to record muscle activities innervated by the ansa cervicalis. The vagus nerve and ansa cervicalis were electrically stimulated during surgery, and electromyography of the vocal cords and muscles innervated by the ansa cervicalis was recorded. The threshold of vagus nerve activation ranged between 0.05 and 0.75 mA. RESULTS: The vagus nerve was successfully identified and differentiated from the nerve root of the ansa cervicalis using this technique. CONCLUSIONS: Intraoperative monitoring of the vagus nerve and ansa cervicalis is useful for safe and effective vagus nerve stimulation.

DOI： 10.1016/j.wneu.2019.07.210

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：English  

Deep brain stimulation (DBS) of the posterior subthalamic nucleus (pSTN), caudal zona incerta (cZI), and prelemniscal radiation (Raprl) has been shown to improve Parkinsonian motor symptoms. We herein report neurophysiological and functional differences among the cZI, Raprl, and pSTN in a 68-year-old male patient with Parkinson's disease (PD). The stereotactic implantation of DBS electrodes in the right STN was performed. Thereafter, a transfrontal trajectory for the left cZI was planned for left side implantation, with the expectation that the electrode entered the pSTN in the case of a posterior brain shift. In the implantation of the DBS lead in the cZI, three microelectrodes were simultaneously placed in an array with the central, medial, and anterior positions placed 2 mm apart to delineate the cZI, Raprl, and pSTN, respectively. A maximal reduction in bradykinesia was obtained from the stimulation of the pSTN at the lowest voltage thresholds, and the voltage threshold for abolishing tremors was lower in the Raprl and cZI than in the pSTN. The left DBS lead was implanted in the pSTN because right-sided bradykinesia was more severe than tremor. The multitrack recording of cZI, Raprl, and pSTN might broaden target selection depending on patients' symptoms.

DOI： 10.2176/nmccrj.cr.2018-0277

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Thalamotomy is an established treatment for medically refractory tremor. Major complications of thalamotomy include cognitive disturbance, paralysis, dysphagia, sensory loss, and speech disturbance. Hemiballism is a rare complication after thalamotomy. We herein present a 74-year-old female patient who developed choreo-ballistic movement after thalamotomy. She was diagnosed with Lewy body dementia at the age of 70 years and exhibited worsening bilateral hand tremor. Her tremor was severe and pharmacoresistant. Left thalamotomy was planned with the trajectory passing through the ventralis intermedius (VIM) nucleus to the posterior subthalamic area (PSA). The right VIM nucleus and PSA were both coagulated with one trajectory, resulting in the immediate amelioration of right hand tremor. However, four days after surgery, choreo-ballistic movement appeared in the right leg and persisted for six months. Furthermore, tremor recurred after one month. Postoperative MRI showed a small coagulated lesion in the subthalamic nucleus. Although choreo-ballistic movement is a rare complication, it needs to be considered, particularly in patients in which the inferior border of the VIM nucleus is targeted.

DOI： 10.1016/j.jocn.2019.05.048

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An electrical cortical stimulation provides important information for functional brain mapping. However, subjective responses (i.e. sensory, visual, and auditory symptoms) are purely detected by patients' descriptions, and may be affected by patients' awareness and intelligence levels. We experienced psychogenic responses in the electrical cortical stimulation of two patients with intractable epilepsy. A sham stimulation was useful for differentiating pseudo-responses from real responses in the electrical cortical stimulation. Inductive questions, long testing durations, and clear cues of stimulation onsets need to be avoided to prevent psychogenic pseudo-responses in the electrical cortical stimulation. Furthermore, a sham stimulation is applicable for detecting pseudo-responses the moment patients show atypical or inexplicable symptoms.

DOI： 10.2176/nmc.tn.2018-0321

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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BACKGROUND: Previous studies have reported the usefulness of intraoperative corticocortical evoked potentials (CCEPs) for preserving language function during brain surgery. OBJECTIVE: This study aimed to assess the influence of depth of anesthesia on CCEP to establish its clinical utility. METHODS: Twenty patients with brain tumors or epilepsy who underwent awake craniotomy were included in this study. Before resection, the electrode plates were placed on the frontal and temporoparietal cortices, and 1-Hz alternating electrical stimuli were delivered to the pars opercularis/pars triangularis in a bipolar fashion. Electrocorticograms from the temporoparietal cortices time-locked to stimuli were averaged to obtain CCEP responses from a state of deep anesthesia until the awake state. The correlation between CCEP waveforms and bispectral index (BIS) was evaluated. RESULTS: CCEP amplitude increased with the increase in the BIS level. CCEP latency decreased in 5 patients and increased in 15 patients under anesthesia compared with the awake state. CCEP amplitudes decreased by 11.3% to 75.2% (median 31.3%) under anesthesia with <65 BIS level. These differences were statistically significant (P < 0.01, Wilcoxon signed-rank test). With respect to CCEP latencies, there was no significant difference between the awake and anesthetic states. CONCLUSIONS: CCEP amplitudes were correlated with depth of anesthesia, whereas CCEP latencies were not affected by anesthesia. The influence of anesthesia should be considered when applying this technique to intraoperative monitoring.

DOI： 10.1016/j.wneu.2018.11.253

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Epilepsy after aneurysmal subarachnoid hemorrhage (post-SAH epilepsy) is a critical complication that influences clinical and social prognoses. However, the underlying mechanisms remain unclear. We investigated the relationship between hemosiderosis and the incidence of post-SAH epilepsy. About 50 patients with aneurysmal SAH who were admitted to Sapporo Medical University and Oji General Hospital between April 2010 and June 2016 were enrolled in this retrospective study. Hemosiderosis detected by T2*-weighted magnetic resonance imaging(MRI) and the incidence of post-SAH epilepsy were retrospectively analyzed. Post-SAH epilepsy was defined as an unprovoked seizures occurring more than 1 week after the onset of SAH. Six patients (12%) developed post-SAH epilepsy. In all patients, hemosiderosis in the cortex or cerebral parenchyma was detected by T2*-weighted MRI. Statistical analyses revealed that hemosiderosis and the co-existence of intracerebral hemorrhage (ICH) related with post-SAH epilepsy (Fisher's exact test, univariate exact logistic regression analysis: P < 0.05). Post-SAH epilepsy was predicted by hemosiderosis and the co-existence of ICH. The present results suggest that hemosiderin is the principal cause of post-SAH epilepsy and may be a predictor of this critical complication.

DOI： 10.2176/nmc.oa.2018-0125

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Peri-electrode edema can occur after deep brain stimulation (DBS). The diagnosis and management of peri-electrode edema may be challenging. We herein report non-infectious peri-electrode edema after the placement of DBS electrodes in patients with Parkinson's disease (PD). Fifteen patients who underwent DBS surgery between 2010 and 2018 at Sapporo Medical University were included to identify post-operative peri-electrode edema. Pre- and post-operative CT and MRI were retrospectively analyzed. Six patients showed hyperintensity around the electrodes on FLAIR/T2 MRI without neurological deficits. Two patients showed limited FLAIR and DWI hyperintensities in deep white matter, and microvessels may have been occluded in these patients. In five patients, MRI revealed extensive FLAIR or T2 hyperintensity in surface white matter around the electrodes without vessel injury, whereas DWI showed no abnormal signals. The eosinophil count was increased in one of these five patients. Peri-electrode edema after DBS surgery is not an uncommon phenomenon, and includes two types: (1) limited edema in deep white matter and (2) extensive edema in surface white matter. Different mechanisms may be associated with these types of edemas.

DOI： 10.1016/j.jocn.2018.11.026

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Language：Japanese   Publisher：(一社)日本神経学会  

Ichushi

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BACKGROUND: The connection between the ventrolateral frontal and temporoparietal cortices has an important role in language function on the language-dominant side and spatial awareness on the nondominant side. However, the laterality of these pathways remains controversial. We investigated the laterality of this connection using corticocortical-evoked potentials (CCEPs). METHODS: From April 2014 to March 2016, 27 patients who had undergone frontotemporal craniotomy were enrolled. With the patients under general anesthesia, subdural electrodes were placed on both frontal and temporoparietal areas intraoperatively. Alternating 1-Hz electrical stimuli were delivered to the pars opercularis and pars triangularis with a stimulus intensity of 10 mA. CCEPs were obtained from temporoparietal areas by averaging the electrocorticogram time-locked to the stimulus onset. The amplitudes and latencies of the CCEP N1 components were compared between the dominant and nondominant sides. RESULTS: The median amplitudes of the CCEPs were 335.1 μV (range, 60.2-750) and 125.65 μV (range, 55.1-634) on the dominant and nondominant sides, respectively. The CCEP amplitudes were significantly larger on the dominant side than on the nondominant side (P = 0.013). In contrast, the median latency was 27.8 ms (range, 19.3-36.6) on the language-dominant side and 28.9 ms (range, 8.9-38.5) on the nondominant side. The latencies were not significantly different between the 2 sides (P = 0.604). CONCLUSIONS: The CCEP amplitudes were significantly larger in the dominant hemisphere. These findings can lead to better hypotheses regarding the relationship between language functions and the development of the network connecting the frontal and temporoparietal cortices.

DOI： 10.1016/j.wneu.2018.08.137

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BACKGROUND AND OBJECTIVE: Although many studies have investigated functional localization by electrical stimulation, the threshold to identify each area remains controversial. The present study aimed to elucidate the threshold of a cortical stimulation for functional mapping. METHODS: We analyzed data from 17 patients with medically intractable epilepsy who underwent a 50-Hz electrical cortical stimulation for functional mapping between October 2013 and May 2017. The symptoms induced by the stimulation and the thresholds of the stimulation for these responses were evaluated. RESULTS: Motor responses were observed after the stimulation of the primary motor cortex, supplementary motor area, and frontal eye field, and sensory responses after the stimulation of the primary and secondary sensory cortex. Regarding negative responses, language impairment was observed after the stimulation of the anterior, posterior, and basal temporal language areas, negative motor responses after the stimulation of the premotor cortex, posterior parietal cortex, and the pre- supplementary motor area, and an impairment in spatial recognition after the stimulation of the right posterior parietal cortex. Negative or positive auditory symptoms were observed with the stimulation of the posterior superior temporal gyrus. The thresholds for positive phenomena were significantly lower than those for negative phenomena (Mann-Whitney U test, P < 0.01), and sensory responses were induced at significantly lower intensities than motor responses (P < 0.01). CONCLUSIONS: Positive and sensory effects are induced by lower intensities than negative and motor responses, respectively. The present results provide not only a practical guide for functional mapping, but also a hierarchal concept of processing in the brain.

DOI： 10.1016/j.wneu.2018.07.059

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OBJECTIVE: This study investigated the function and networks of the auditory cortices in the posterior lateral superior temporal area (PLST) using a combination of electrical cortical stimulation and diffusion tensor imaging (DTI). METHODS: Seven patients with intractable focal epilepsy in which the PLST auditory cortices were identified during the electrical cortical stimulation were enrolled in this study (left side: four patients, right side: three patients). Electrical stimulation at 50 Hz was applied to the chronically implanted subdural electrodes to identify the PLST auditory cortices. DTI was used to identify the subcortical fibers originating from the PLST auditory cortices found by electrical stimulation. RESULTS: Electrical stimulation of the right PLST auditory cortices induced hearing impairment in three patients and left side stimulation elicited hearing illusory sounds in four patients. DTI detected the middle longitudinal fasciculus (MLF) in all patients, the superior longitudinal fasciculus (SLF) in six patients and the inferior fronto-occipital fasciculus (IFOF) in three patients, originating from the PLST auditory cortices. CONCLUSION: This study suggests different functional roles between the right and left PLST auditory cortices, and the networks originating from these areas. SIGNIFICANCE: MLF, SLF and IFOF might be associated with the auditory processing.

DOI： 10.1016/j.clinph.2018.07.014

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本脳循環代謝学会  

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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OBJECTIVE: The present study aimed to investigate the threshold and distribution of afterdischarges (ADs) with cortical electrical stimulation for functional brain mapping. METHOD: We retrospectively analyzed data from 11 patients with medically intractable epilepsy who underwent 50-Hz cortical electrical stimulation for functional mapping followed by resection. These patients became seizure free for more than six months. The threshold and distribution of ADs induced by the stimulation were evaluated. RESULTS: The median threshold was 6 mA (range: 2-15 mA) for the frontal lobe, 8 mA (3-15 mA) for the temporal lobe, 6 mA (2-15 mA) for the parietal lobe, and 6 mA (4-12 mA) for the occipital lobe. No significant interlobar differences were observed in AD thresholds. No significant differences were noted between within and outside epileptogenic zones. The distribution of ADs, remote spread was observed in all patients, reflecting fronto-parieto-temporal connections, as well as contiguous spread. The stimulation of premotor areas, the inferior parietal lobule, supplementary motor area, and basal temporal areas appeared to induce ADs in remote cortices. CONCLUSION: While no locational differences were observed in AD thresholds, each brain region showed a characteristic pattern for AD spread. Remote AD spread needs to be considered for safe functional mapping.

DOI： 10.1016/j.jocn.2018.06.039

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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Meningiomas rarely exhibit cystic lesions with mural nodules, and may be misdiagnosed as intraparenchymal cystic tumors. We herein present a 64-year-old woman with a cystic lesion and enhancing mural nodule in the left temporal lobe accompanied by peritumoral brain edema. Differential diagnoses included low-grade gliomas, hemangioblastoma, and cystic meningioma. Gross total resection of the tumor was achieved through a temporal surgical approach. Intraoperative findings showed that the tumor was an extraparenchymal tumor. The cyst was covered by an extraparenchymal thin membrane and the cystic fluid was yellowish in color. The final result of the pathological examination was microcystic meningioma, WHO grade I. Although intraparenchymal tumors, such as hemangioblastoma, ganglioglioma, pilocytic astrocytoma, and pleomorphic xanthoastrocytoma, commonly display this MRI pattern, meningioma needs to be included in the differential diagnosis.

DOI： 10.18999/nagjms.80.3.431

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DOI： 10.1212/WNL.0000000000005826

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Language：Japanese   Publisher：Movement Disorder Society of Japan (MDSJ)  

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Language：Japanese   Publisher：(株)全日本病院出版会  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2018&ichushi_jid=J03505&link_issn=&doc_id=20180622090013&doc_link_id=%2Fap5meree%2F2018%2F000223%2F013%2F0119-0129%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fap5meree%2F2018%2F000223%2F013%2F0119-0129%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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OBJECTIVE: To retrospectively determine the safety and efficacy of combined chemotherapy with carmustine (BCNU) wafer, bevacizumab, and temozolomide plus radiotherapy in patients with newly diagnosed glioblastoma (GBM). METHODS: A total of 54 consecutive newly diagnosed GBMs were resected at our institution between 2010 and 2016. Twenty-nine patients underwent BCNU wafer implantation into the resection cavity followed by standard radiochemotherapy with temozolomide (TMZ, Stupp regimen) plus additional bevacizumab treatment between 2013 and 2016. Twenty-five patients who underwent resection without BCNU implantation between 2010 and 2012 were enrolled as a control group; these patients were treated with the Stupp regimen and did not receive bevacizumab. This retrospective study included evaluation of progression-free survival and overall survival, plus comparisons between the combined therapy group and the control group. RESULTS: There were no significant differences in age, sex, Karnofsky Performance Status on admission, isocitrate dehydrogenase 1/2 mutation ratio, or resection rate between the combined and standard therapy groups. The median overall survival in the combined therapy group and control group was 24.2 months and 15.30, respectively (P = 0.027). The median progression-free survival was 16.8 months and 7.30 months, respectively (P = 0.009). Overall, the incidence of adverse events leading to discontinuation of the study drug was similar between the treatment groups, except for infection, which was more common in the combined treatment group and required repeat surgery. CONCLUSIONS: The combined therapy showed higher efficacy compared with standard therapy in patients with GBM. Therefore, combined therapy seems to be effective with an acceptable toxicity profile.

DOI： 10.1016/j.wneu.2018.02.070

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Language：Japanese   Publisher：日本脳神経CI学会  

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Language：Japanese   Publisher：(株)医学書院  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2018&ichushi_jid=J01228&link_issn=&doc_id=20180216100014&doc_link_id=10.11477%2Fmf.1436203695&url=https%3A%2F%2Fdoi.org%2F10.11477%2Fmf.1436203695&type=%E5%8C%BB%E6%9B%B8.jp_%E3%82%AA%E3%83%BC%E3%83%AB%E3%82%A2%E3%82%AF%E3%82%BB%E3%82%B9&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00024_2.gif

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.11477/mf.1436203695

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Language：Japanese   Publisher：(株)メディカ出版  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2018&ichushi_jid=J03120&link_issn=&doc_id=20180109220003&doc_link_id=issn%3D0917-1495%26volume%3D28%26issue%3D1%26spage%3D22&url=http%3A%2F%2Fwww.pieronline.jp%2Fopenurl%3Fissn%3D0917-1495%26volume%3D28%26issue%3D1%26spage%3D22&type=PierOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00005_2.gif

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Language：Japanese   Publisher：(株)メディカ出版  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2018&ichushi_jid=J03120&link_issn=&doc_id=20180109220001&doc_link_id=issn%3D0917-1495%26volume%3D28%26issue%3D1%26spage%3D6&url=http%3A%2F%2Fwww.pieronline.jp%2Fopenurl%3Fissn%3D0917-1495%26volume%3D28%26issue%3D1%26spage%3D6&type=PierOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00005_2.gif

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Language：Japanese   Publisher：(公社)日本小児科学会  

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BACKGROUND: The frontal aslant tract is a deep frontal pathway connecting the superior frontal gyrus (SFG) to Broca area. This fiber is assumed to be associated with language functions, especially speech initiation and spontaneity. The aim of this study was to electrophysiologically investigate this network using corticocortical evoked potentials (CCEPs). METHODS: This study enrolled 8 patients with brain tumors or medically intractable focal epilepsies who underwent frontal craniotomy over the language-dominant side. All patients underwent CCEP recordings during tumor resection or during invasive evaluation for epilepsy surgery. Alternating 1-Hz electrical stimuli were delivered to pars opercularis (pO) and pars triangularis (pT), corresponding to Broca area, and SFG via the subdural grid electrodes with intensity of 10 mA. Electrocorticograms from SFG and pO/pT time-locked to 50 stimuli were averaged in each trial to obtain CCEP responses. RESULTS: In all patients, stimulation of pO/pT induced CCEP responses in SFG. CCEP responses were recorded in lateral SFG in 5 patients and in supplementary motor areas in 4 patients. Reciprocality was observed in 7 patients in the stimulation of SFG. CCEP responses were significantly faster at SFG from pO/pT than at pO/pT from SFG (Wilcoxon signed rank test, P = 0.028). CONCLUSIONS: The present study demonstrated a corticocortical network connecting Broca areas and SFG in a reciprocal manner. Our findings might provide new insight into language and motor integration.

DOI： 10.1016/j.wneu.2017.07.166

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Intraoperative monitoring of the motor evoked potential (MEP) during cerebral aneurysm surgery has been widely used to confirm surgical safety. In this study, we retrospectively analyzed the influence of the MEP amplitude resulting from temporal occlusion of the parent artery, and appropriate judgement in the surgery was discussed. Ten patients underwent temporal occlusion of the parent artery during aneurysm surgery, and five of these patients showed a decrease in the MEP amplitude following temporal arterial occlusion. Clinical factors in patients with and without MEP decrease were compared. The time gap between the surgical procedure and the MEP change and recovery was then investigated. A decrease in the MEP amplitude caused by temporal occlusion had a significantly higher occurrence compared with permanent clip failure. The time from the release procedure to MEP amplitude recovery was relatively longer than the time from the occlusion procedure to the decrease in MEP amplitude. The time from release procedure to MEP amplitude recovery showed a weak correlation with the parent artery occlusion time. There is a time gap between releasing the temporal arterial occlusion and MEP recovery that is similar to temporal parent arterial occlusion and the MEP decrease. The cause of MEP amplitude should be judged carefully, and influence of parent artery temporal occlusion should be taken into consideration during aneurysm clipping.

DOI： 10.1016/j.jocn.2017.06.002

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Language：Japanese   Publisher：(公社)日本小児科学会  

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OBJECTIVE: The basal temporal language area (BTLA) is considered to have several functions in language processing; however, its brain network is still unknown. This study investigated the distribution and networks of the BTLA using a combination of electric cortical stimulation and diffusion tensor imaging (DTI). METHOD: 10 patients with intractable focal epilepsy who underwent presurgical evaluation with subdural electrodes were enrolled in this study (language dominant side: 6 patients, language nondominant side: 4 patients). Electric stimulation at 50 Hz was applied to the electrodes during Japanese sentence reading, morphograms (kanji) reading, and syllabograms (kana) reading tasks to identify the BTLA. DTI was used to identify the subcortical fibers originating from the BTLA found by electric stimulation. RESULTS: The BTLA was found in 6 patients who underwent implantation of the subdural electrodes in the dominant hemisphere. The BTLA was located anywhere between 20 mm and 56 mm posterior to the temporal tips. In 3 patients, electric stimulation of some or all areas within the BTLA induced disturbance in reading of kanji words only. DTI detected the inferior longitudinal fasciculus (ILF) in all patients and the uncinate fasciculus (UF) in 1 patient, originating from the BTLA. ILF was detected from both kanji-specific areas and kanji-nonspecific areas. CONCLUSION: This study indicates that the network of the BTLA is a part of a ventral stream and is mainly composed of the ILF, which acts as a critical structure for lexical retrieval. ILF is also associated with the specific processing of kanji words.

DOI： 10.1016/j.wneu.2017.06.116

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Reflex seizures are epileptic events triggered by specific external stimuli, or less commonly, internal mental stimuli. Understanding the characteristics of reflex seizures is important to elucidate the mechanisms underlying network abnormalities in epileptic conditions. This report details a patient with medically intractable reflex seizures provoked by sensory stimuli to the patient's right foot. Single-photon emission computed tomography (SPECT) during the seizure induced by sensory stimulation showed hyperperfusion in broad sensory-motor networks (dorsal column-medial lemniscus pathway, left thalamus, bilateral postcentral gyri and posterior parietal cortices, left supplementary motor area (SMA), and left paracentral lobule) and left caudateputamen. The irritative zones and ictal onset zone were localized to the left medial frontoparietal (SMA, anterior and middle cingulate gyrus, and paracentral lobule) and lateral posterior parietal cortices, as evidenced by amelioration of reflex seizures following intracranial electroencephalography and surgical resection of these areas. The neuroradiological and electrophysiological findings in our case study illustrate that the mechanism of reflex seizures may be associated with hyperexcitability of the broad sensory-motor networks, including the basal ganglia. Disconnection of these networks is necessary to treat reflex seizures.

DOI： 10.2176/nmccrj.cr.2017-0031

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

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BACKGROUND: Dilatation of the microvascular diameter is recognized in moyamoya disease and referred to as microvascularization. The purpose of this study was to characterize the cortical microvascularization in moyamoya disease using imaging analysis, and to explore the developmental mechanism of the collateral network around the cortical surface. METHODS: A total of 20 hemispheric sides of 14 patients with moyamoya disease were included in this study. From the intraoperative images, cortical surface images were extracted, and binary images were subsequently created. Then the ratio of the microvessels of the brain surface (vascular fraction; VF) and the box-counting fractal dimension (Db) values were calculated. The VF and Db values in the moyamoya disease group were then compared with those in atherosclerotic disease and nonischemic disease groups, and assessed in terms of clinical and radiologic factors. RESULTS: VF was significantly higher in the moyamoya disease group compared with the atherosclerotic disease group, and Db was significantly higher in the moyamoya disease group compared with the atherosclerotic disease and nonischemic disease groups. In the moyamoya disease group, VF showed a moderate correlation with magnetic resonance angiography (MRA) score. Moreover, Db was significantly higher in the pediatric patients, in the presence of ischemic symptoms, and in the presence of ivy sign, and Db showed a moderate correlation with MRA score and cerebral blood flow in moyamoya disease. CONCLUSIONS: In the patients with moyamoya disease, the cortical microvascularization exhibited increased Db and dilatation of the pial arteries. In moyamoya disease, cortical microvascularization is associated with clinical and radiologic factors. This microvascularization might be a compensatory mechanism in the ischemic condition in moyamoya disease.

DOI： 10.1016/j.wneu.2017.06.124

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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OBJECTIVE: To evaluate motor function during neuroendoscopic resectioning of deep-seated brain tumors using endoscopically guided depth electrodes. METHODS: For 12 cases of thalamic tumors, including high-grade gliomas, germinomas, and malignant lymphomas, depth electrodes were inserted using endoscopic guides between the tumor and the pyramidal tract in the thalamus. Motor-evoked potentials (MEPs) were continuously recorded during neuroendoscopic resectioning of the tumors. RESULTS: Monitoring of MEP responses using depth electrodes in all 12 cases was successful. The minimum stimulus intensity threshold required to induce MEP responses was 3 mA. Gross total or subtotal resections were successful with this technique for all patients with glioma. No additional neurologic impairments were found after surgery in any of the cases. CONCLUSIONS: Continuous MEP measurement using depth electrodes can serve as a new monitoring technique for endoscopic resectioning of deep-seated brain tumors.

DOI： 10.1016/j.wneu.2017.05.048

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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OBJECTIVE: This study aimed to identify the subtype of interictal ripples that help delineate the epileptogenic zone in neocortical epilepsy. METHODS: Totally 25 patients with focal neocortical epilepsy who had invasive electroencephalography (EEG) evaluation and subsequent surgery were included. They were followed up for at least 2years. Interictal ripples (80-250Hz) and fast ripples (250-500Hz) during slow-wave sleep were identified. Neocortical ripples were defined as type I ripples when they were superimposed on epileptiform discharges, and as type II ripples when they occurred independently. Resection ratio was calculated to present the extent to which the cortical area showing an interictal event or the seizure onset zone (SOZ) was completely removed. RESULTS: Fast ripples and types I and II ripples were found in 8, 19, and 21 patients, respectively. Only the higher resection ratio of interictal fast or type I ripples was correlated to the Engel 1a surgical outcome. CONCLUSIONS: Type I ripples could assist in localizing the epileptogenic zone in neocortical epilepsy. SIGNIFICANCE: Type I and fast ripples both may be pathological high-frequency oscillations.

DOI： 10.1016/j.clinph.2017.03.033

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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Language：Japanese   Publisher：(株)メディカルレビュー社  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2017&ichushi_jid=J05023&link_issn=&doc_id=20170516180001&doc_link_id=%2Fai1epild%2F2017%2F001101%2F001%2F0004-0006%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fai1epild%2F2017%2F001101%2F001%2F0004-0006%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2017&ichushi_jid=J03414&link_issn=&doc_id=20170419390002&doc_link_id=%2Fff2rinsy%2F2017%2F004502%2F003%2F0087-0090%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fff2rinsy%2F2017%2F004502%2F003%2F0087-0090%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：日本てんかん学会-北海道地方会  

Ichushi

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Language：Japanese   Publisher：(一社)日本神経学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：English   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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DOI： 10.4103/0366-6999.184473

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OBJECT The frontal and insular fiber network in humans remains largely unknown. This study investigated the connectivity of the frontal and anterior insular network in humans using cortico-cortical evoked potential (CCEP). METHODS This retrospective analysis included 18 patients with medically intractable focal epilepsy who underwent stereoelectroencephalography and CCEP. Alternating 1-Hz electrical stimuli were delivered to parts of the frontal lobe and anterior insula (prefrontal cortex [PFC], ventrolateral and dorsolateral premotor area [vPM and dPM, respectively], presupplementary motor area [pre-SMA], SMA, frontal operculum, and anterior insula). A total of 40-60 stimuli were averaged in each trial to obtain CCEP responses. The distribution of CCEP was evaluated by calculating the root mean square of CCEP responses. RESULTS Stimulation of the PFC elicited prominent CCEP responses in the medial PFC and PMs over the ipsilateral hemisphere. Stimulation of the vPM and dPM induced CCEP responses in the ipsilateral frontoparietal areas. Stimulation of the pre-SMA induced CCEP responses in the ipsilateral medial and lateral frontal areas and contralateral pre-SMA, whereas stimulation of the SMA induced CCEP responses in the bilateral frontoparietal areas. Stimulation of the frontal operculum induced CCEP responses in the ipsilateral insula and temporal operculum. CCEPs were observed in the ipsilateral medial, lateral frontal, and frontotemporal operculum in the anterior insular stimulation. Stimulation of the vPM and SMA led to the network in the dominant hemisphere being more developed. CONCLUSIONS Various regions within the frontal lobe and anterior insula were linked to specific ipsilateral and contralateral regions, which may reflect distinct functional roles.

DOI： 10.3171/2015.6.JNS15622

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BACKGROUND: To evaluate the effectiveness of bypass surgery for moyamoya disease, electrocorticography was first evaluated. METHODS: A total of 13 hemispheres in 9 patients with moyamoya disease were included in this study. To record the spectral power of electrocorticography continuously during the bypass procedure, a 4 × 5 subdural electrode grid was placed on the middle frontal gyrus. The changes in spectral power before and after bypass surgery were evaluated and compared with those in a control group. The correlation between changes in spectral power and regional cerebral blood flow was analyzed. RESULTS: The average spectral power ratio of the beta band per total band in moyamoya disease before bypass surgery was lower than that of controls (P = 0.027), and the significance disappeared after bypass surgery (P = 0.800). The spectral power levels of the beta band and gamma band were increased in moyamoya disease after bypass surgery (P < 0.001). Changes in spectral power of the beta band correlated with changes in regional cerebral blood flow (P = 0.002). CONCLUSIONS: The spectral power of the beta band on electrocorticography was focally suppressed in patients with moyamoya disease, and the suppression was reversible by revascularization surgery. Steno-occlusive ischemic changes in moyamoya disease might cause suppression of neurophysiologic activity, and the present results provide insight into the potential neuromodulatory role of revascularization surgery.

DOI： 10.1016/j.wneu.2016.04.087

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It has been reported that epilepsy patients had higher risk of sudden death than that of the general population. However, in Japan, there is very little literature on the observational research conducted on sudden fatal events in epilepsy. We performed a single-center, retrospective study on all the out-of-hospital cardiac arrest (OHCA) patients treated in our emergency department between 2007 and 2013. Among the OHCA patients, we extracted those with a history of epilepsy and then analyzed the characteristics of the fatal events and the background of epilepsy. From 1,823 OHCA patients, a total of 10 cases were enrolled in our study. The median age was 34 years at the time of the incident [9-52 years; interquartile range (IQR), 24-45]. We determined that half of our cases resulted from external causes of death such as drowning and suffocation and the other half were classified as sudden unexpected death in epilepsy (SUDEP). In addition, asphyxia was implicated as the cause in eight cases. Only the two near-drowning patients were immediately resuscitated, but the remaining eight patients died. The median age of first onset of epilepsy was 12 years (0.5-30; IQR, 3-21), and the median disease duration was 25 years (4-38; IQR, 6-32). Patients with active epilepsy accounted for half of our series and they were undergoing poly anti-epileptic drug therapy. The fatal events related to epilepsy tended to occur in the younger adult by external causes. An appropriate therapeutic intervention and a thorough observation were needed for its prevention.

DOI： 10.2176/nmc.oa.2015-0285

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Invasive evaluations play important roles in identifying epileptogenic zones and functional areas in patients with intractable focal epilepsy. This article reviews the usefulness, methods, and limitations of invasive evaluations for epilepsy surgery. Invasive evaluations include various types of intracranial electrodes such as stereotactically implanted intracranial depth electrodes (stereo-EEG), chronic subdural electrodes, and intraoperative electrocorticography. Scalp EEG is distorted by the skull, meninges, and skin. On the other hand, intracranial electrodes provide spatial information with higher resolution than scalp electrodes, thereby enabling further delineation of epileptogenic zones and mapping of functional areas with electrical stimulation. In addition, intracranial electrodes record a wide frequency range of electrical activity, which is not possible with scalp electrodes. The very slow potentials in ictal recordings, known as ictal direct current (DC) shifts and ictal/interictal high frequency oscillations, such as ripples (100-200 Hz) and fast ripples (200-500 Hz), have been correlated with the ictal onset zone and are a sensitive and specific marker for epileptogenicity. Furthermore, several studies reported that the electrical stimulation of epileptogenic zones elicited enhanced cortical evoked potentials, abnormal delayed or repetitive responses, and fast ripples. These responses may assist in the delineation of the epileptogenic cortex as a potential new marker. There are definite risks of complications associated with the use of intracranial electrodes. However, when an invasive evaluation is selected based on careful consideration of the risks and benefits, it provides useful information for establishing a strategy for epilepsy surgery.

DOI： 10.2176/nmc.ra.2015-0319

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Language：Japanese   Publishing type：Research paper (scientific journal)  

Neurological deficits following coil embolization of anterior circulation aneurysms due to the toxicity of contrast medium are rare. Here, we describe a patient with mild consciousness impairment and left hemiparesis following coil embolization of a large right middle cerebral artery aneurysm without evidence of ischemia or hemorrhage, who recovered completely with conservative treatment. The patient's clinical course and radiological findings led us to conclude that the neurological deficits were due to the toxic effect of contrast medium used during the coil embolization.

DOI： 10.11477/mf.1436203294

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Language：Japanese   Publisher：(一社)日本小児神経外科学会  

Ichushi

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Language：Japanese   Publisher：(株)医学書院  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2016&ichushi_jid=J01228&link_issn=&doc_id=20160525150005&doc_link_id=1390283684979332608&url=https%3A%2F%2Fcir.nii.ac.jp%2Fcrid%2F1390283684979332608&type=CiNii&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00003_2.gif

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Language：Japanese   Publisher：(一社)日本小児神経外科学会  

Ichushi

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OBJECTIVE: During brain surgery, there are difficulties associated with identifying subcortical fibers with no clear landmarks. We evaluated the usefulness of cortical evoked potentials with subcortical stimuli (subcortico-cortical evoked potential [SCEP]) in identifying subcortical fibers intraoperatively. METHODS: We used SCEP to identify the pyramidal tract in 4 patients, arcuate fasciculus in 1 patient, and both in 2 patients during surgical procedures. After resection, a 1 × 4-electrode plate was placed on the floor of the removal cavity and 1-Hz alternating electrical stimuli were delivered to this electrode. A 4 × 5 recording electrode plate was placed on the central cortical areas to map the pyramidal tract and temporoparietal cortical areas for the arcuate fasciculus. SCEPs were obtained by averaging electrocorticograms time locked to the stimulus onset. RESULTS: The subcortical stimulation within 15 mm of the target fiber induced cortical evoked potentials in the corresponding areas, whereas the stimulation apart from 20 mm did not. Five patients showed transient worsening of neurologic symptoms after surgery. However, all patients recovered. CONCLUSIONS: SCEP was useful for identifying subcortical fibers and confirmed the preservation of these fibers. This technique is expected to contribute to the effectiveness and safety of resective surgery in patients with lesions close to eloquent areas.

DOI： 10.1016/j.wneu.2015.10.043

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Language：Japanese   Publisher：(NPO)日本脳神経外科救急学会  

Ichushi

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Language：Japanese   Publisher：(独)国立病院機構姫路医療センター  

Ichushi

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Language：Japanese   Publisher：(株)メディカ出版  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2015&ichushi_jid=J03120&link_issn=&doc_id=20151110140006&doc_link_id=issn%3D0917-1495%26volume%3D25%26issue%3D11%26spage%3D1179&url=http%3A%2F%2Fwww.pieronline.jp%2Fopenurl%3Fissn%3D0917-1495%26volume%3D25%26issue%3D11%26spage%3D1179&type=PierOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00005_2.gif

Ichushi

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Language：Japanese   Publisher：大道学館出版部  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2015&ichushi_jid=J01556&link_issn=&doc_id=20151102430004&doc_link_id=%2Fam3daidc%2F2015%2F009210%2F004%2F1251-1254%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fam3daidc%2F2015%2F009210%2F004%2F1251-1254%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Ichushi

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(株)最新医学社  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2015&ichushi_jid=J00516&link_issn=&doc_id=20150617010013&doc_link_id=%2Fap7saisa%2F2015%2F007006%2F014%2F1097-1101%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fap7saisa%2F2015%2F007006%2F014%2F1097-1101%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Ichushi

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Language：Japanese   Publisher：(一社)日本小児神経外科学会  

Ichushi

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Language：English   Publishing type：Research paper (scientific journal)  

Papez proposed a network for higher brain function, which is termed the limbic network. However, the in vivo human limbic network has not been established. We investigated the connectivity of the human limbic system using corticocortical evoked potential (CCEP). This retrospective analysis included 28 patients with medically intractable focal epilepsy who underwent stereoelectroencephalography (SEEG) and CCEP. Alternating 1 Hz electrical stimuli were delivered to parts of the limbic system [anterior and posterior hippocampus, temporal pole, parahippocampal gyrus (PHG), amygdala, anterior (ACG) and posterior cingulate gyrus (PCG), medial and lateral orbitofrontal cortex (OF)]. A total of 40-60 stimuli were averaged in each trial to obtain CCEP responses. CCEP distributions were evaluated by calculating the root mean square (RMS) of CCEP responses. Anterior hippocampal stimulation elicited prominent CCEP responses in medial and lateral temporal structures, PCG, medial OF and insula over the ipsilateral hemisphere. Posterior hippocampal stimulation induced CCEP responses in the ipsilateral medial and lateral temporal structures and PCG. The findings also revealed connections from temporal pole to the ipsilateral medial temporal structures, and connections from PHG to the ipsilateral hippocampus and PCG. The amygdala projected to broad areas including the ipsilateral medial and lateral temporal structures, medial and lateral frontal areas, the cingulate gyrus, insula and inferior parietal lobule. ACG and PCG showed connections to the ipsilateral medial fronto-parietal areas and connections to bilateral medial temporo-parieto-occipital and lateral parieto-occipital areas, respectively. Medial and lateral OF stimulation induced responses in the adjacent cortices. This study revealed that various regions within the limbic network are intimately connected in reverberating circuits and are linked to specific ipsilateral and contralateral regions, which may reflect distinct functional roles.

DOI： 10.1016/j.cortex.2014.06.018

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BACKGROUND: Intracerebral hemorrhage is the most feared complication of intravenous thrombolysis for acute ischemic stroke. Such hemorrhage usually occurs within or at the margin of ischemic or manifestly infarcted brain tissue. A patient with Trousseau syndrome who developed multiple extra-ischemic hemorrhages following intravenous thrombolysis is described. CASE DESCRIPTION: An 80-year-old Japanese man with no other underlying disease was diagnosed with unresectable advanced lung cancer (stage IV) without brain metastasis and had not yet been treated. The patient suddenly presented with disturbance of consciousness, right hemiplegia, and total aphasia, and was admitted to our hospital. Magnetic resonance imaging revealed acute cerebral infarction extending from the basal ganglia to the corona radiata of the left cerebrum and multiple small areas of bilateral cerebral cortices. Cardiogenic cerebral embolism was considered among the differential diagnoses, but the brain natriuretic peptide level was within the normal range, and no arrhythmias such as atrial fibrillation were observed. With no other causes, the patient was diagnosed with Trousseau syndrome due to hypercoagulability associated with the advanced lung cancer. The patient received intravenous tissue plasminogen activator (t-PA) at 96 minutes after onset of symptoms. His symptoms partially improved, but they suddenly deteriorated at 84 minutes after the thrombolysis. A computed tomography (CT) scan immediately after the neurological deterioration revealed a subcortical hemorrhage in the left occipital lobe. A repeat CT scan the day after onset showed enlargement of the left occipital hemorrhage and two new subcortical hemorrhages in the right frontal and right temporal lobes. These hemorrhages were located in areas remote from the acute ischemic lesions. CONCLUSION: To the best of our knowledge, this is the first reported case of multiple extra-ischemic hemorrhages following intravenous thrombolysis in a patient with Trousseau syndrome. The course of this case suggests that intravenous t-PA administration for acute ischemic stroke with Trousseau syndrome may be associated with a higher risk of intracranial hemorrhage.

DOI： 10.1186/s40064-015-0920-z

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Language：Japanese   Publisher：(NPO)日本脳神経血管内治療学会  

Ichushi

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Language：Japanese   Publisher：(株)医学書院  

Other Link： https://search.jamas.or.jp/default/link?pub_year=2014&ichushi_jid=J01228&link_issn=&doc_id=20141017050011&doc_link_id=1390283684977785728&url=https%3A%2F%2Fcir.nii.ac.jp%2Fcrid%2F1390283684977785728&type=CiNii&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00003_2.gif

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Language：Japanese   Publishing type：Research paper (scientific journal)  

Distal anterior choroidal artery aneurysms are quite rare, and appropriate treatment timing and methods remain unclear. Direct surgery of these aneurysms is difficult due to their deep location, small size, and angioarchitecture;however, pseudoaneurysms might disappear spontaneously with conservative treatment. A 65-year-old man with a history of hypertension was admitted to our hospital with a 5-day history of sudden headache and nausea. Computed tomography revealed an intraventricular hematoma located mainly in the right lateral ventricle. Cerebral angiography 7 days after onset revealed a right distal anterior choroidal artery aneurysm and proximal right middle cerebral artery occlusion caused by atherosclerotic changes. Endovascular coil embolization was performed under general anesthesia 14 days after onset. Preoperative angiography demonstrated definite enlargement of the aneurysm and stasis of the contrast agent in the aneurysm in the venous phase. Detachable platinum coils were delivered into the aneurysm and parent artery. The patient was discharged neurologically intact after the procedure. Follow-up angiography 3 months after coil embolization showed complete occlusion of the aneurysm. In recent years, endovascular surgery has emerged as a less invasive treatment option. Early treatment should be considered for patients with ruptured distal anterior choroidal artery aneurysm because these aneurysms might grow and re-rupture in the short term.

DOI： 10.11477/mf.1436200011

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BACKGROUND: Although stereoelectroencephalography (SEEG) has been shown to be a valuable tool for preoperative decision making in focal epilepsy, there are few reports addressing the utility and safety of SEEG methodology applied to children and adolescents. OBJECTIVE: To present the results of our early experience using SEEG in pediatric patients with difficult-to-localize epilepsy who were not considered candidates for subdural grid evaluation. METHODS: Thirty children and adolescents with the diagnosis of medically refractory focal epilepsy (not considered ideal candidates for subdural grids and strip placement) underwent SEEG implantation. Demographics, electrophysiological localization of the hypothetical epileptogenic zone, complications, and seizure outcome after resections were analyzed. RESULTS: Eighteen patients (60%) underwent resections after SEEG implantations. In patients who did not undergo resections (12 patients), reasons included failure to localize the epileptogenic zone (4 patients); multifocal epileptogenic zone (4 patients); epileptogenic zone located in eloquent cortex, preventing resection (3 patients); and improvement in seizures after the implantation (1 patient). In patients who subsequently underwent resections, 10 patients (55.5%) were seizure free (Engel class I) and 5 patients (27.7%) experienced seizure improvement (Engel class II or III) at the end of the follow-up period (mean, 25.9 months; range, 12 to 47 months). The complication rate in SEEG implantations was 3%. CONCLUSION: The SEEG methodology is safe and should be considered in children/adolescents with difficult-to-localize epilepsy. When applied to highly complex and difficult-to-localize pediatric patients, SEEG may provide an additional opportunity for seizure freedom in association with a low morbidity rate.

DOI： 10.1227/NEU.0000000000000453

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Language：English   Publisher：(一社)日本てんかん学会  

Ichushi

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Stereo-electroencephalography (SEEG) has advantages for exploring deeper epileptic foci. Nevertheless, SEEG can only sample isolated cortical areas and its spatial limitation, with the inability to record contiguous cortical regions, may cause difficulties in interpretation. In light of these limitations, the authors describe the hybrid technique of SEEG and subdural strip electrode placement. The hybrid technique was used for a presurgical evaluation in four patients with intractable epilepsy. Initially, the depth electrodes were inserted with a robotic stereotactic system. Thereafter, a skin incision and a small craniectomy were performed at the entry point of the strip electrode trajectory. The dura was opened and, under live fluoroscopic guidance, strip electrodes were slid into the subdural space. In these patients, the additional subdural strip electrodes provided (1) information regarding the precise description of seizure spread in the cortical surface adjacent to the subdural space, (2) identification of epileptogenic zones located near the crown, (3) more precise definition of functional cortex and (4) a better delineation of the interface between epileptogenic zones and functional cortex. This hybrid technique provides additional data compared to either technique alone, offering superior understanding of the dynamics of the epileptic activity and its interaction with functional cortical areas.

DOI： 10.1016/j.jocn.2013.12.014

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A cephalic aura is a common sensory aura typically seen in frontal lobe epilepsy. The generation mechanism of cephalic aura is not fully understood. It is hypothesized that to generate a cephalic aura extensive cortical areas need to be excited. We report a patient who started to have cephalic aura after right frontal lobe resection. Magnetoencephalography (MEG) showed interictal spike and ictal change during cephalic aura, both of which were distributed in the right frontal region, and the latter involved much more widespread areas than the former on MEG sensors. The peculiar seizure onset pattern may indicate that surgical modification of the epileptic network was related to the appearance of cephalic aura. We hypothesize that generation of cephalic aura may be associated with more extensive cortical involvement of epileptic activity than that of interictal activity, in at least a subset of cases.

DOI： 10.1016/j.jocn.2013.11.024

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BACKGROUND: Stereotactic laser ablation offers an advantage over open surgical procedures for treatment of epileptic foci, tumors, and other brain pathology. Robot-assisted stereotactic laser ablation could offer an accurate, efficient, minimally invasive, and safe method for placement of an ablation catheter into the target. OBJECTIVE: To determine the feasibility of placement of a stereotactic laser ablation catheter into a brain lesion with the use of robotic assistance, via a safe, accurate, efficient, and minimally invasive manner. METHODS: A laser ablation catheter (Visualase, Inc) was placed by using robotic guidance (ROSA, Medtech Surgical, Inc) under general anesthesia into a localized epileptogenic periventricular heterotopic lesion in a 19-year-old woman with 10-year refractory focal seizure history. The laser applicator (1.65 mm diameter) position was confirmed by using magnetic resonance imaging (MRI). Ablation using the Visualase system was performed under multiplanar imaging with real-time thermal imaging and treatment estimates in each plane. A postablation MRI sequence (T1 postgadolinium contrast injection) was used to immediately confirm the ablation. RESULTS: MRI showed accurate skin entry point and trajectory, with the applicator advanced to the lesion's distal boundary. Ablation was accomplished in less than 3 minutes of heating. The overall procedure, from time of skin incision to end of last ablation, was approximately 90 minutes. After confirmation of proper lesioning by using a T1 contrast-enhanced MRI, the applicator was removed, and the incision was closed using a single stitch. No hemorrhage or other untoward complication was visualized. The patient awoke without any complication, was observed overnight after admitting to a regular floor bed, and was discharged to home the following day. CONCLUSION: This technique, using a combination of Visualase laser ablation, ROSA robot, and intraoperative MRI, facilitated a safe, efficacious, efficient, and minimally invasive approach that could be used for placement of 1 or multiple electrodes in the future.

DOI： 10.1227/NEU.0000000000000286

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Patients with medically intractable epilepsy often undergo invasive evaluation and surgery, with a 50% success rate. The low success rate is likely due to poor identification of the epileptogenic zone (EZ), the brain area causing seizures. This work introduces a new method using functional magnetic resonance imaging (fMRI) with simultaneous direct electrical stimulation of the brain that could help localize the EZ, performed in five patients with medically intractable epilepsy undergoing invasive evaluation with intracranial depth electrodes. Stimulation occurred in a location near the hypothesized EZ and a location away. Electrical recordings in response to stimulation were recorded and compared to fMRI. Multiple stimulation parameters were varied, like current and frequency. The brain areas showing fMRI response were compared with the areas resected and the success of surgery. Robust fMRI maps of activation networks were easily produced, which also showed a significant but weak positive correlation between quantitative measures of blood-oxygen-level-dependent (BOLD) activity and measures of electrical activity in response to direct electrical stimulation (mean correlation coefficient of 0.38 for all acquisitions that produced a strong BOLD response). For four patients with outcome data at 6 months, successful surgical outcome is consistent with the resection of brain areas containing high local fMRI activity. In conclusion, this method demonstrates the feasibility of simultaneous direct electrical stimulation and fMRI in humans, which allows the study of brain connectivity with high resolution and full spatial coverage. This innovative technique could be used to better define the localization and extension of the EZ in intractable epilepsies, as well as for other functional neurosurgical procedures.

DOI： 10.1089/brain.2014.0225

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OBJECT: Despite its long-reported successful record, with almost 60 years of clinical use, the technical complexity regarding the placement of stereoelectroencephalography (SEEG) depth electrodes may have contributed to the limited widespread application of the technique in centers outside Europe. The authors report on a simplified and novel SEEG surgical technique in the extraoperative mapping of refractory focal epilepsy. METHODS: The proposed technique was applied in patients with medically refractory focal epilepsy. Data regarding general demographic information, method of electrode implantation, time of implantation, number of implanted electrodes, seizure outcome after SEEG-guided resections, and complications were prospectively collected. RESULTS: From March 2009 to April 2012, 122 patients underwent SEEG depth electrode implantation at the Cleveland Clinic Epilepsy Center in which the authors' technique was used. There were 65 male and 57 female patients whose mean age was 33 years (range 5-68 years). The group included 21 pediatric patients (younger than 18 years). Planning and implantations were performed in a single stage. The time for planning was, on average, 33 minutes (range 20-47 minutes), and the time for implantation was, on average, 107 minutes (range 47-150 minutes). Complications related to the SEEG technique were observed in 3 patients. The calculated risk of complications per electrode was 0.18%. The seizure-free rate after SEEG-guided resections was 62% in a mean follow-up period of 12 months. CONCLUSIONS: The authors report on a safe, simplified, and less time-consuming method of SEEG depth electrode implantation, using standard and widely available surgical tools, making the technique a reasonable option for extraoperative monitoring of patients with medically intractable epilepsy in centers lacking the Talairach stereotactic armamentarium.

DOI： 10.3171/2013.11.JNS13635

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BACKGROUND: The rolandic cortex exhibits spontaneous rhythmic activity. This oscillation can be modulated by somatosensory stimulation and voluntary movement. The purpose of this study is to elucidate the influence of sensory input on the rolandic oscillation in comparison with movement-related oscillation. METHODS: Magnetic brain rhythms were recorded in nine healthy subjects in two sessions: electrical stimulation (STIM) of the digital nerve and self-paced movement (SPM) of the right index finger. Thereafter, 10 and 20 Hz oscillatory activities were compared between the two sessions with temporal spectral evolution analysis. RESULTS: Sensory input altered the rolandic oscillations even under no movement conditions. As for 10 Hz ERD in the STIM session, three subjects showed a contralateral dominant pattern, whereas the remaining subjects showed a bilateral pattern. In spite of this individual variability, ERD showed comparable amplitude in both sessions. However, ERSs in the SPM session were larger than that in the STIM session. These findings might reflect the activation of neural networks common to sensory and motor systems followed by the inhibition of the other surrounding cortical areas. CONCLUSIONS: Our results suggest that rolandic oscillations may reflect the coordination of sensory and motor systems in the neural networks including both sensory and motor systems.

DOI： 10.1016/j.jns.2013.12.011

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OBJECTIVE: Posterior cingulate epilepsy (PCE) is misleading because the seizure onset is located in an anatomically deep and semiologically silent area. This type of epilepsy is rare and has not been well described yet. Knowledge of the characteristics of PCE is important for the interpretation of presurgical evaluation and better surgical strategy. The purpose of this study was to better characterise the clinical and neurophysiological features of PCE. METHODS: This retrospective analysis included seven intractable PCE patients. Six patients had postcingulate ictal onset identified by stereotactic EEG (SEEG) evaluations. One patient had a postcingulate tumour. We analysed clinical semiology, the scalp EEG/SEEG findings and cortico-cortical evoked potential (CCEP). RESULTS: The classifications of scalp EEG were various, including non-localisible, lateralised to the seizure onset side, regional parieto-occipital, regional frontocentral and regional temporal. Three of seven patients showed motor manifestations, including bilateral asymmetric tonic seizures and hypermotor seizures. In these patients, ictal activities spread to frontal (lateral premotor area, orbitofrontal cortex, supplementary motor area, anteior cingulate gyrus) and parietal (precuneus, posterior cingulate gyrus, inferior parietal lobule (IPL), postcentral gyrus) areas. Four patients showed dialeptic seizures or automotor seizures, with seizure spread to medial temporal or IPL areas. CCEP was performed in four patients, suggesting electrophysiological connections from the posterior cingulate gyrus to parietal, temporal, mesial occipital and mesial frontal areas. CONCLUSIONS: This study revealed that the network from the posterior cingulate gyrus and the semiology of PCE (motor manifestation vs dialeptic/automotor seizure) varies depending upon the seizure spread patterns.

DOI： 10.1136/jnnp-2013-305604

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DOI： 10.1007/s10072-013-1434-5

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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The purpose of this study was to investigate the connectivity from the negative motor area and to elucidate the mechanism of negative motor phenomena. We report the results of cortico-cortical evoked potentials (CCEPs) by electrical stimulation of the primary motor area (MI), primary sensory area (SI), primary (PNMA) and supplementary negative motor area (SNMA) in eight epilepsy patients who underwent intracranial electrode placement. Alternating 1-Hz electrical stimuli were delivered to MI (six patients), SI (five), PNMA (six) and SNMA (two). CCEPs were recorded by averaging electrocorticograms time-locked to the stimuli. Stimulation of MI, SI and PNMA induced CCEP responses in the premotor area (PM), pre- and postcentral gyri, posterior parietal cortex and the temporo-parietal junction. Upon SNMA stimulation, CCEP responses were detected in the prefrontal cortex, PM, pre- and postcentral gyri, supplementary motor area (SMA) and preSMA. Compared with stimulation of SI and MI, PNMA stimulation revealed a broader distribution of CCEP responses in the frontal or parietal association cortex, indicating the importance of the fronto-parietal network associated with a higher level of motor control. We concluded that these connections are associated with motor control and that the negative motor phenomenon results from impairment of the organization of movements.

DOI： 10.1016/j.cortex.2012.08.026

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OBJECTIVE: To investigate the human limbic system using cortico-cortical evoked potential (CCEP), which reveals the brain networks. METHODS: Five patients with nonlesional medically intractable focal epilepsy with ictal onset outside the limbic system were enrolled. All patients underwent stereoelectroencephalogram electrode implantation in order to delineate the epileptogenic zone. Alternating 1Hz electrical stimuli were delivered to the hippocampus and posterior cingulate gyrus. A total of sixty stimuli were averaged in each trial to obtain CCEP responses. RESULTS: Hippocampal stimulation elicited prominent CCEP responses in the posterior cingulate gyrus. The latencies of early (N1) and late (N2) negative peak ranged 20-60 ms and 102-175 ms respectively. In addition, CCEP responses were observed in the posterior parahippocampal gyrus, medial superior frontal gyrus (SFG) and orbitofrontal cortex. Stimulation of posterior cingulate contacts induced CCEPs in the hippocampus with N1 and N2 latencies of 25-43 ms and 90-234 ms respectively in all five patients. CONCLUSION: This finding supports the assertion that the hippocampus is connected with the posterior cingulate gyrus, posterior parahippocampal gyrus, medial SFG and orbitofrontal cortex. The hippocampus and posterior cingulate gyrus have a bidirectional network through the cingulum. SIGNIFICANCE: The present study provides new insight into the human limbic network.

DOI： 10.1016/j.clinph.2013.01.024

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PURPOSE: In contrast to EEG, which has guidelines for interpretation and a plethora of textbooks, the full range of activity seen in magnetoencephalography (MEG) has not been fleshed out. Currently, magnetoencephalographers apply criteria for EEG waveforms to MEG signals based on an assumption that MEG activity should have morphology that is similar to EEG. The purpose of this article was to show the characteristic MEG profile of positive occipital sharp transients of sleep. METHODS: Simultaneous MEG-EEG recordings of two cases are shown. RESULTS: In both the cases, the morphologic features of positive occipital sharp transients of sleep in MEG vary and sometimes mimic epileptic spikes. CONCLUSION: This report raises a caution that a normal variant may have an even more epileptic appearance on MEG than on EEG. Using the simultaneously recorded EEG to avoid misinterpretation of spikey-looking positive occipital sharp transients of sleep in MEG is a natural and prudent practice.

DOI： 10.1097/WNP.0b013e31827681a3

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PURPOSE: This study analyzes falsely localizing pseudotemporal ictal EEG patterns, to test if it is possible to differentiate them from those in "true" temporal lobe epilepsy. METHODS: We retrospectively studied 33 patients who had epilepsy surgery and a favorable outcome (Engel I), belonging to three groups: 10 patients (37 seizures) with pseudotemporal ictal patterns (PT), 12 patients (45 seizures) with mesial temporal epilepsy because of hippocampal sclerosis (HS), and 11 patients (41 seizures) with neocortical temporal epilepsy (NT). Ictal EEGs were analyzed visually according to predetermined criteria and by using a source localization program (BESA5.1). The topographies of interictal discharges were compared among the three groups. RESULTS: Ictal patterns and locations overlapped across all the groups. The initial onset patterns in NT were less likely to localize to one temporal region as compared with the other groups (P < 0.008). Rhythmic temporal theta as later pattern was seen significantly more frequently in HS than in NT (P < 0.001). All seizures in PT spread to the contralateral side compared with 73 of 86 (85%) of "true temporal" seizures (P < 0.05). Source analysis of the ictal discharge and topographic distribution of interictal discharges were not able to separate the three groups. CONCLUSIONS: Pseudotemporal ictal patterns are morphologically indistinguishable from true temporal ictal patterns. Although statistically more common in hippocampal sclerosis, rhythmic theta pattern can be seen as a result of propagation from extratemporal sites.

DOI： 10.1097/WNP.0b013e3182872f70

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Although previous studies have investigated the sensitivity of electroencephalography (EEG) and magnetoencephalography (MEG) to detect spikes by comparing simultaneous recordings, there are no published reports that focus on the relationship between spike dipole orientation or sensitivity of scalp EEG/MEG and the "gold standard" of intracranial recording (stereotactic EEG). We evaluated two patients with focal epilepsy; one with lateral temporal focus and the other with insular focus. Two MEG recordings were performed for both patients, each recorded simultaneously with initially scalp EEG, based on international 10-20 electrode placement with additional electrodes for anterior temporal regions, and subsequently stereotactic EEG. Localisation of MEG spike dipoles from both studies was concordant and all MEG spikes were detected by stereotactic EEG. For the patient with lateral temporal epilepsy, spike sensitivity of MEG and scalp EEG (relative to stereotactic EEG) was 55 and 0%, respectively. Of note, in this case, MEG spike dipoles were oriented tangentially to scalp surface in a tight cluster; the angle of the spike dipole to the vertical line was 3.6 degrees. For the patient with insular epilepsy, spike sensitivity of MEG and scalp EEG (relative to stereotactic EEG) was 83 and 44%, respectively; the angle of the spike dipole to the vertical line was 45.3 degrees. For the patient with lateral temporal epilepsy, tangential spikes from the lateral temporal cortex were difficult to detect based on scalp 10-20 EEG and for the patient with insular epilepsy, it was possible to evaluate operculum insular sources using MEG. We believe that these findings may be important for the interpretation of clinical EEG and MEG.

DOI： 10.1684/epd.2013.0554

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Epilepsy is defined as a disorder of the brain characterized by an enduring predisposition to experience epileptic seizures and the neurobiological, cognitive, psychological, and social difficulties relating to the condition. An epileptic spasm (ES) is a type of seizure characterized by clusters of short contractions involving axial muscles and proximal segments. However, the precise mechanism of ESs remains unknown. Despite the potential of magnetoencephalography (MEG) as a tool for investigating the neurophysiological mechanism of ESs, it has been difficult to use this methodology due to magnetic artifacts attributable to patient movement. We report on an 8-year-old girl suffering from intractable epileptic spasms from the age of 7 months. She was diagnosed with possible Aicardi syndrome [corrected] (AGS), characterized by the triad of callosal agenesis, infantile spasms, and chorioretinal lacunae. She is now intellectually delayed and suffers from intractable ES. We used both MEG and electroencephalography to investigate her epilepsy. The recording captured two series of spasm clusters. Spikes were clearly identified with MEG in about four-fifths of all spasms but were identified poorly or not at all in the remainder. MEG findings support previous studies that used intracranial electrodes to analyze patients with ESs and that showed variability in ES-associated spikes in terms of manner of cortical involvement and magnitude. Given the limitations of intracranial electrodes, such as sampling restrictions and invasiveness, MEG may be a helpful tool for non-invasively investigating the unique pathophysiological profile of focal-onset ESs.

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The coexistence of focal and idiopathic generalized epilepsy (IGE) is rarely observed, and the mechanism underlying this situation remains unknown. We report a 13-year-old girl with well-controlled generalized epilepsy and medically-refractory left temporal lobe epilepsy. She underwent intracranial EEG recording, which demonstrated two characteristic seizure patterns of generalized ictal onset and left mesial temporal onset. In addition, two types of interictal spike distribution, including the left mesial temporal region and generalized spikes, were also supportive of the coexistence of left mesial temporal lobe epilepsy and IGE. Thereafter, a left anterior temporal lobectomy and post-surgical medication significantly improved her seizure outcome. This case illustrates the importance of considering surgical management for patients with medically-intractable focal epilepsy coexisting with generalized epilepsy.

DOI： 10.1016/j.yebeh.2012.10.026

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OBJECTIVE: To investigate the connectivity associated with the reorganized language network in patients with temporal lobe epilepsy (TLE) using cortico-cortical evoked potential (CCEP), which reveals the brain networks. METHODS: Six patients with intractable TLE who underwent chronic intracranial electrode placement and revealed an atypical distribution of posterior language areas (Wernicke's areas) were studied. Alternating 1 Hz electrical stimuli were delivered to the anterior language areas (Broca's areas). CCEPs were recorded by averaging electrocorticograms time-locked to stimuli from the subdural electrodes. Thereafter, the posterior language areas identified by the electrical cortical mapping and CCEP distributions were compared by calculating the root mean square of CCEP responses. RESULTS: CCEP responses were observed in various areas within the temporal, temporo-parietal or temporo-occipital area. The correlation between CCEP distributions and posterior language areas revealed two patterns. In two patients, the posterior language areas were located within CCEP distribution, but out of the maximum responses in the temporal lobe. On the other hand, parts of the language areas were outside CCEP-positive areas in four patients. CONCLUSION: Our results suggest that language reorganization might be associated with a functional shift from the termination of anterior-posterior language connection to the surrounding cortices. It should be noted that language areas can be identified outside the anterior-posterior language connection.

DOI： 10.1016/j.eplepsyres.2012.07.008

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OBJECTIVE: To clarify the clinical and neurophysiological profiles of fronto-parietal opercular epilepsy in which epileptic spikes are detected with magnetoencephalography (MEG) but not with scalp electroencephalography (EEG). METHODS: Four patients presented with epileptic spikes localized to the fronto-parietal opercular cortex, which were only appreciated following MEG recordings. RESULTS: In all cases, seizure semiology suggested early activation of the operculum and lower peri-rolandic cortex consistent with the somatotopic organization of this region, i.e. tingling sensation involving the throat and hemi-face or contralateral upper limb, and spasms of the neck and throat. MEG spikes were localized in the fronto-parietal operculum. Three of the four patients underwent invasive electrocorticography and/or stereo-EEG recordings, and spikes were confirmed to arise from the estimated area of MEG dipole localization. Two patients remained seizure-free for over 1 year after resection of the epileptogenic region; the other patient declined resective surgery due to proximity to the language cortex. CONCLUSION: This study demonstrates the usefulness of MEG in localizing spikes arising from within the fronto-parietal opercular regions, and implies that MEG may provide localizing information in patients with symptoms suggestive of opercular epilepsy, even if scalp EEG recordings fail to disclose any epileptogenic activities.

DOI： 10.1016/j.eplepsyres.2012.05.003

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Language：English   Publisher：(一社)日本てんかん学会  

Ichushi

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DOI： 10.1016/j.clineuro.2012.01.017

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OBJECTIVE: To better understand the process of ictal propagation in epilepsy by using cortico-cortical evoked potential (CCEP), which reveals the brain networks. METHODS: Intracranial EEG recordings of 11 seizures from 11 patients with pharmacoresistant focal epilepsy were studied to identify the propagation sites and times. Six patients had a history of secondary generalization (Gen (+) group) and five patients did not (Gen (-) group). Thereafter repetitive 1Hz bipolar electrical stimuli were applied to the ictal onset zones and CCEPs were recorded by averaging electrocorticograms. RESULTS: The propagation of contiguous spread was significantly faster than non-contiguous spread (p=0.033). In four patients, CCEP amplitudes were significantly larger in the ictal propagation area than out of the propagation area. However, the distribution of CCEP responses was not necessarily consistent with the ictal propagation area as a whole. Furthermore, the ictal propagation areas out of CCEP-positive areas were significantly broader in Gen (+) group than Gen (-) group (p=0.017). CONCLUSION: The present findings suggest that contiguous spread is faster than non-contiguous spread, which can be explained by the enhancement of excitability around the ictal onset area. Furthermore, there is a group of fibers that is "closed" during the seizures and secondary generalization might be more associated with the impairment of cortical inhibition over the broad cortical area rather than direct connection.

DOI： 10.1016/j.eplepsyres.2012.03.004

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We report a 39-year-old man with bilateral mesial temporal lobe epilepsy. He was implanted with a responsive brain stimulator (RNS System) with two depth electrodes placed in the bimesial temporal structures. After the implantation, his seizure frequency decreased by up to 50%. Electrocorticogram recorded by the RNS device revealed the right-sided predominance of seizure onset. He underwent a right temporal lobectomy, and his seizure significantly improved. After the RNS System was restarted 107 days after the temporal lobectomy, he has been seizure free for more than 1.5 years. However, the implanted device continued to record residual ictal activities at the posterior aspect of the right hippocampus and delivered electrical stimuli to suppress the seizure activities. Our report indicates the importance of electrocorticographic recordings by the RNS System to modify the treatment strategy and the complementary effect of surgical resection and brain stimulation in the treatment of epilepsy.

DOI： 10.1016/j.yebeh.2012.06.009

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A movement compensation (MC) algorithm may help to evaluate seizure focus in magnetoencephalography despite patient movement. We report a boy whose ictal MEG focus was localized to the same sublobar region before and after head turning when MC was applied, but which was erroneously localized to a different area without MC. This study provides the first clinical evidence for utility of MC in magnetoencephalography for localizing focal seizures.

DOI： 10.1016/j.eplepsyres.2012.03.014

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Pituitary apoplexy is defined as a sudden loss of blood supply to the pituitary gland, leading to tissue necrosis and hemorrhage. Its clinical symptoms are characterized by sudden onset of headache, nausea, vomiting, ophthalmic symptoms and hormonal dysfunction. A 65-year-old woman presented with left-sided ptosis and blurred vision. These ophthalmic symptoms gradually worsened for one month without headache, visual acuity and field deficit. Neuro-ophthalmic examination revealed left oculomotor nerve palsy. Magnetic resonance imaging (MRI) revealed a round mass lesion in the left cavernous sinus, which was initially suspected as thrombosed cerebral aneurysm or hemorrhagic Rathke's cleft cyst. The mass lesion was finally diagnosed as pituitary apoplexy. The patient underwent trans-sphenoidal surgery and oculomotor nerve palsy improved after the surgery. Early diagnosis and treatment including surgical decompression are crucially important in patients with oculomotor nerve palsy in pituitary apoplexy, but the symptoms of pituitary apoplexy may slowly progress. It should be noted that pituitary apoplexy could be misdiagnosed as cerebral aneurysm or Rathke's cleft cyst.

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Spontaneous intracerebral hemorrhage represents 20 to 30% of all stroke patients in Japan. However, the treatment strategy of intracerebral hematoma remains controversial. Stereotactic hematoma evacuation is minimally invasive surgery and is beneficial for clot removal with limited tissue damage. The purpose of this study was to investigate the factors affecting motor recovery after stereotactic hematoma evacuation. This retrospective analysis included 30 patients with spontaneous thalamic or putaminal hemorrhage who underwent stereotactic hematoma evacuation. We compared age, presurgical muscle strength, hematoma volume and removal rate between the patients who showed improvement of motor function (improved group) and the patients associated with no motor improvement (unchanged group). Twenty-one patients were classified into the improved group and nine patients into the unchanged group. Statistical analysis revealed that age in the improved group was significantly younger than in the unchanged group (p < 0.01), whereas there was no significant difference in presurgical muscle strength, hematoma volume and removal rate between the two groups. The present results revealed that stereotactic hematoma evacuation is attributable to the improvement of motor function, especially in the younger population, indicating the importance of cortical reorganization during post-surgical rehabilitation. In addition, this procedure could provide functional improvement in severely disabled patients. Proper patient selection to receive this therapy would be beneficial for further advances of this technique. The present result might be useful in elucidating the mechanism of motor recovery and proper patient selection for this technique.

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OBJECTIVE: To better understand pathological neuronal excitation in epilepsy by comparing cortico-cortical evoked potential (CCEP) responses in regions with different ictal onset patterns: focal paroxysmal fast (PF) and repetitive spiking (RS). METHODS: Fourteen patients undergoing invasive monitoring (six patients with PF and eight with RS) were studied with CCEPs. A repetitive 1 Hz bipolar electrical stimulus was applied to both the ictal onset region (iCCEP) and to a control region (nCCEP) and CCEPs were recorded from the surrounding electrodes. The two groups were compared by subtracting the amplitude of nCCEP from that of iCCEP (CCEP(ictal-control)) at each stimulus intensity, and then normalizing the amplitudes of iCCEP at maximum stimulus intensity by dividing by nCCEP (CCEP(ictal/control)). RESULTS: The CCEP response to stimulation in the ictal onset region was significantly larger than to control stimulation for both ictal patterns (paroxysmal fast: P=0.02, repetitive spiking: P<0.01), with repetitive spiking group amplitudes higher than the paroxysmal fast group (CCEP(ictal-control): P<0.01 and CCEP(ictal/control): P=0.04). CONCLUSIONS: Pro-epileptic excitability is more accentuated in regions showing an ictal repetitive spiking pattern than a paroxysmal fast pattern. SIGNIFICANCE: These findings confirm in a new way that cortical excitability varies depending on the ictal onset pattern.

DOI： 10.1016/j.clinph.2011.06.030

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Language：English   Publisher：(一社)日本臨床神経生理学会  

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Ictal singing has been rarely reported and the neural networks underlying this specific symptom remain unknown. We report a nineteen-year-old man with medically refractory seizures who exhibited ictal singing and laughing. He underwent intracranial stereotactic EEG recording which demonstrated ictal activity in medial and dorsolateral regions of the left frontal lobe in the generation of ictal singing. Thereafter, a left frontal resection of the superior and middle frontal gyri made him seizure-free. Among the previously reported cases of ictal singing, the symptomatogenic zones included bilateral frontal and temporal lobes. The wide variance of ictal onset zones suggests that the mechanism of ictal singing is probably related to the recruitment of music-related neural networks in different regions of both hemispheres rather than activation of a specific cortical region.

DOI： 10.1016/j.yebeh.2011.07.019

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

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Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVE: To determine whether patients with neocortical epilepsy show evidence for increased excitability measured by cortico-cortical evoked potentials (CCEPs) in ictal-onset regions. METHODS: In patients undergoing intracranial recordings with subdural electrodes for epilepsy surgery, we measured amplitudes, latencies, and stimulus thresholds of CCEPs near ictal onset zones (iCCEPs), and compared with adjacent neocortex not associated with ictal EEG (nCCEP). CCEP amplitude and latency measurements were made with each stimulation site, using graded stimulation intensities. RESULTS: Ten patients were included in this study. CCEPs were recorded in eight of 10 patients. The first negative (N1) iCCEP amplitude was higher than that of nCCEP in seven of the eight patients. In the group analysis, this difference was statistically significant. In three of these patients, the difference was individually significant. In one patient, the amplitude was higher in nCCEP than iCCEP and the area selected as nCCEP was within primary eloquent cortex. There was no significant difference seen in latency changes or stimulus threshold. CONCLUSIONS: Accentuated CCEP amplitudes near ictal onset zones could reflect an increased excitability of the cortex associated with the epileptogenic zone in some patients with neocortical epilepsy. The response of the neocortex to low-frequency stimulation may vary depending on the presence or absence of intrinsic epileptogenicity.

DOI： 10.1684/epd.2010.0334

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Language：Japanese   Publisher：(一社)日本脳神経外科学会  

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Quantitative evaluation of the sensory disturbance of the tongue is important clinically. However, because the conventional electrophysiological approach to the peripheral nerve cannot be used in the mandible owing to the deep route of the lingual nerve, we applied evoked potentials in the central nervous system. Somatosensory evoked magnetic fields (SEFs) following electric stimulation were recorded in 10 healthy subjects by means of pin electrodes placed on the tongue mucosa. Three or four components (P25m, P40m, P60m, and P80m) were identified over the contralateral hemisphere with unilateral stimulation. Because none of the components were consistently detected in all subjects, we evaluated the root mean square (RMS) of 18 channels over the contralateral hemisphere. To estimate the activated cortical response, we calculated the difference in mean RMS amplitude between 10 and 150 ms and that of the baseline period (aRMS=RMS[10, 150]-RMS[-50, -5]). The aRMS values for right-sided and left-sided stimulation were 10.18+/-7.92 and 10.99+/-8.98 fT/cm, respectively, and the mean laterality index, expressed by [(left-right)/(left+right)] was 0.025+/-0.104. This parameter can be useful for evaluating patients with unilateral sensory abnormality of the tongue.

DOI： 10.1016/j.neures.2008.07.004

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The present study investigated the sensitivity of magnetoencephalography (MEG) for spikes depending on sensor type in patients with mesial temporal epileptic focus. We recorded MEG in 6 patients with mesial temporal epileptic focus using two sensor types (magnetometer and gradiometer) simultaneously. The number of spikes detected and the corresponding equivalent current dipole (ECD) parameters (distance from the coordinated head center (radius), and dipole moment) were evaluated with respect to sensor type. Among 426 MEG 'consensus spikes' determined by 3 reviewers, 378 spikes satisfied the predetermined criteria for source localization. Comparing ECD parameters, spikes detected by magnetometer alone displayed a smaller radius and larger dipole moment than those detected by gradiometer alone. Spikes estimated in the mesial temporal area were more frequently detected by magnetometer alone (38.5%) than by gradiometer alone (11.5%), whereas spikes in the lateral temporal area were detected less by magnetometer alone (3.7%) than by gradiometer alone (53.9%). The present results suggest that a magnetometer is advantageous for spike detection in patients with mesial temporal epileptic focus. This also implies the higher sensitivity of magnetometer for deep sources.

DOI： 10.1016/j.neuroimage.2008.03.038

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Language：Japanese   Publisher：(一社)日本脊髄外科学会  

Ichushi

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Language：Japanese   Publisher：(NPO)日本脳神経外科救急学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本脳神経外科学会  

Ichushi

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OBJECTIVE: To clarify the clinical usefulness of preoperative fibre-tracking in affected pyramidal tracts for intraoperative monitoring during the removal of brain tumours from patients with motor weakness. METHODS: We operated on 10 patients with mild to moderate motor weakness caused by brain tumours located near the pyramidal tracts under local anaesthesia. Before surgery, we performed fibre-tracking imaging of the pyramidal tracts and then transferred this information to the neuronavigation system. During removal of the tumour, motor function was evaluated with motor evoked potentials elicited by cortical/subcortical electrical stimulation and with voluntary movement. RESULTS: In eight patients, the locations of the pyramidal tracts were estimated preoperatively by fibre-tracking; motor evoked potentials were elicited on the motor cortex and subcortex close to the predicted pyramidal tracts. In the remaining two patients, in which fibre-tracking of the pyramidal tracts revealed their disruption surrounding the tumour, cortical/subcortical electrical stimulation did not elicit responses clinically sufficient to monitor motor function. In all cases, voluntary movement with mild to moderate motor weakness was extensively evaluated during surgery and was successfully preserved postoperatively with appropriate tumour resection. CONCLUSIONS: Preoperative fibre-tracking could predict the clinical usefulness of intraoperative electrical stimulation of the motor cortex and subcortical fibres (ie, pyramidal tracts) to preserve affected motor function during removal of brain tumours. In patients for whom fibre-tracking failed preoperatively, awake surgery is more appropriate to evaluate and preserve moderately impaired muscle strength.

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Language：Japanese   Publisher：(一社)日本消化器外科学会  

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OBJECT: The authors evaluated the clinical impact of combining functional neuronavigation with subcortical electrical stimulation to preserve motor function following the removal of brain tumors. METHODS: Forty patients underwent surgery for treatment of brain tumors located near pyramidal tracts that had been identified by fiber tracking. The distances between the electrically stimulated white matter and the pyramidal tracts were measured intraoperatively with tractography-integrated functional neuronavigation, and correlated with subcortical motor evoked potentials (MEPs) and clinical symptoms during and after resection of the tumors. Motor function was preserved after appropriate tumor resection in all cases. In 18 of 20 patients, MEPs were elicited from the subcortex within 1 cm of the pyramidal tracts as measured using intraoperative neuronavigation. During resection, improvement of motor weakness was observed in two patients, whereas transient mild motor weakness occurred in two other patients. In 20 patients, the distances between the stimulated subcortex and the estimated pyramidal tracts were more than I cm, and MEPs were detected in only three of these patients following stimulation. CONCLUSIONS: Intraoperative functional neuronavigation and subcortical electrical stimulation are complementary techniques that may facilitate the preservation of pyramidal tracts around 1 cm of resected tumors.

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OBJECTIVE: To identify the fibers originating from the dorsal premotor cortex (dorsal PMC) that contribute to motor-evoked potentials (MEP), we have applied integrated functional neuronavigation and awake surgery during removal of an epileptic cortical dysplasia located in the right premotor cortex. METHODS: Chronic subdural electrodes were employed for functional mapping during a routine invasive evaluation for intractable epilepsy. After the fibers originating from the dorsal PMC were plotted into the tractography-integrated functional neuronavigation, subcortical MEPs and clinical symptoms were examined during resection of the epileptogenic dorsal PMC. RESULTS: During removal of the epileptogenic area, MEPs were elicited by electrical stimulation of the fibers originating from the dorsal PMC, which were separated from the pyramidal tracts from the precentral gyrus. Resection of the dorsal PMC and its fibers caused a transient dysmetric movement of the left toe without motor weakness. CONCLUSION: Functional corticospinal tract fibers originating from the dorsal PMC can be defined and removed safely under local anesthesia with the aid of integration of functional neuronavigation and subcortical electrical stimulation.

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OBJECT: The utility of subcortical electrical stimulation and fiber tracking were compared to estimate the pyramidal tract near brain tumors. METHODS: In 22 patients, the white matter at the bottom of a tumor was electrically stimulated near the fiber tracking of the pyramidal tract shown on a neuronavigation system. The distance between the center of the fiber tracking of these tracts and the stimulated region was measured and defined as the motor evoked potential (MEP) response. The MEP was consistently produced at distances less than 7 mm (six patients), but was consistently absent at distances more than 13 mm (seven patients) from the fiber tracking of the pyramidal tracts. In the nine patients in whom the distance was between 8 and 12 mm, an MEP was elicited when stimulation was applied at the level of the corona radiata. Motor function was preserved or even improved with appropriate tumor resection in all patients. CONCLUSIONS: The anteroposteriorly running superior longitudinal fasciculus could cause complications in the fiber tracking of upper-extremity motor pathways at the level of the corona radiata. During resection of tumors located near the corona radiata, subcortical electrical stimulation should be applied at some distance from the pyramidal tract, as estimated by fiber tracking.

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Ichushi

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Language：Japanese   Publisher：(一社)日本てんかん学会  

Ichushi

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Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVE: The perirolandic regions were studied by extensive electrical stimulation to clarify the topography and somatotopic distribution of negative motor areas (NMAs) and examine the clinical significance of these areas. METHODS: We evaluated the cortical function elicited by electrical stimulation in 30 patients with tumors or intractable epilepsy. The somatotopic distribution of NMAs was examined by localizing these regions using Talairach's bicommissural reference system. NMAs within the lesions of two patients were removed under local anesthesia. RESULTS: We obtained negative motor responses following the stimulation of 30 electrodes in 15 patients. On the lateral brain surface, the majority of NMAs for the upper extremities were distributed broadly throughout the premotor cortex, while NMAs for the tongue were only found in the inferior frontal gyrus of the dominant hemisphere. During removal of the NMAs within the lesions of two patients, we documented transient hand clumsiness in one patient. CONCLUSIONS: NMAs were widely distributed throughout the perirolandic area, as well as the previously reported regions in the inferior frontal gyrus. These areas likely function in the control of skilled movements; dysfunction of such movements transiently follows resection of these regions, but is subsequently well compensated for after surgery. SIGNIFICANCE: The localization and consequences of resection of NMAs suggests their clinical significance in motor control.

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The authors evaluated adverse effects of intracarotid propofol injection during a Wada test and their risk factors in 58 patients. Nineteen patients had an adverse effect, mostly in patients receiving more than 10 mg. For patients older than age 55 years or those requiring an injection dose greater than 20 mg to produce hemiplegia, propofol should be injected slowly and patients monitored for excitatory movements.

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Language：Japanese   Publisher：認知神経科学会  

Ichushi

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We report here an intractable epilepsy case with fairly typical clinicoradiological features of dysembryoplastic neuroepithelial tumor (DNT), which means onset of seizures at a young age accompanying a medial temporal cystic lesion enclosed in cortical dysplasia (CD). The medial cystic lesion was composed of two morphologically distinct components; one was oligo-like and the other showed some tendency toward neuronal and glial differentiation, even though they were morphologically different from a so-called specific glioneural element (SGE). Epileptiform discharges were detected not only on the medial lesion but also on the lateral inferior temporal gyrus, which was confirmed as CD. According to both histopathological and clinical features, we named the lesion a nonspecific form of DNT.

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Difficulty swallowing due to damage of the vagus nerve is one of the most devastating complications of surgery in and around the medulla oblongata; therefore, intraoperative anatomical and functional evaluation of this nerve is crucial. The authors applied endotracheal tube surface electrodes to record electromyography (EMG) activity from vocal cords innervated by the vagus nerve. The vagal nucleus or rootlet was electrically stimulated during surgery and vocalis muscle EMG activities were displayed by auditory and visual signals. This technique was used successfully to identify the vagus motor nerve and evaluate its integrity during surgery. The advantages of this method compared with the use of needle electrodes include safe simple electrode placement and stable recording during surgery. In cases involving a pontine cavernoma pressing the nucleus or a jugular foramen tumor encircling the rootlet, this method would be particularly valuable. Additional studies with a larger number of patients are needed to estimate the significance of this method as a means of functional monitoring to predict clinical function.

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Language：Japanese   Publisher：日本脳腫瘍病理学会  

Ichushi

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Language：Japanese   Publisher：大阪市医学会  

Ichushi

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Language：Japanese   Publisher：(公財)田附興風会医学研究所北野病院  

Ichushi

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Language：Japanese   Publisher：(株)にゅーろん社  

Ichushi

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Language：Japanese   Publisher：(公財)田附興風会医学研究所北野病院  

Ichushi

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Total pages：118p   Language：Japanese  

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Total pages：133p   Language：Japanese  

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Event date： 2022.6

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