Details of a Researcher

Papers - ENATSU Rei

Division display 181 - 200 of about 228 ／ All the affair displays >>

江夏怜

臨床神経生理学 ( (一社)日本臨床神経生理学会 ) 41 ( 5 ) 323 - 323 2013.10

Cortical negative motor network in comparison with sensorimotor network: a cortico-cortical evoked potential study.

Rei Enatsu, Riki Matsumoto, Zhe Piao, Timothy O'Connor, Karl Horning, Richard C Burgess, Juan Bulacio, William Bingaman, Dileep R Nair

Cortex; a journal devoted to the study of the nervous system and behavior 49 ( 8 ) 2080 - 96 2013.09 [International journal]

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 PubMed

In vivo human hippocampal cingulate connectivity: a corticocortical evoked potentials (CCEPs) study.

Yuichi Kubota, Rei Enatsu, Jorge Gonzalez-Martinez, Juan Bulacio, John Mosher, Richard C Burgess, Dileep R Nair

Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology 124 ( 8 ) 1547 - 56 2013.08 [International journal]

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 PubMed

Magnetoencephalography correlate of EEG POSTS (positive occipital sharp transients of sleep).

Yosuke Kakisaka, Zhong I Wang, Rei Enatsu, Anne-Sophie Dubarry, John C Mosher, Andreas V Alexopoulos, Richard C Burgess

Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society 30 ( 3 ) 235 - 7 2013.06 [International journal]

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 PubMed

Pseudotemporal ictal patterns compared with mesial and neocortical temporal ictal patterns.

Sherif A Elwan, Norman K So, Rei Enatsu, William E Bingaman

Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society 30 ( 3 ) 238 - 46 2013.06 [International journal]

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 PubMed

Sensitivity of scalp 10-20 EEG and magnetoencephalography.

Yosuke Kakisaka, Rafeed Alkawadri, Zhong I Wang, Rei Enatsu, John C Mosher, Anne-Sophie Dubarry, Andreas V Alexopoulos, Richard C Burgess

Epileptic disorders : international epilepsy journal with videotape 15 ( 1 ) 27 - 31 2013.03 [International journal]

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 PubMed

Magnetoencephalography reveals a unique neurophysiological profile of focal-onset epileptic spasms.

Yosuke Kakisaka, Ajay Gupta, Rei Enatsu, Zhong I Wang, Andreas V Alexopoulos, John C Mosher, Anne-Sophie Dubarry, Naomi Hino-Fukuyo, Richard C Burgess

The Tohoku journal of experimental medicine 229 ( 2 ) 147 - 51 2013.02 [Domestic journal]

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.

PubMed

Reorganization of posterior language area in temporal lobe epilepsy: a cortico-cortical evoked potential study.

Rei Enatsu, Yuichi Kubota, Yosuke Kakisaka, Juan Bulacio, Zhe Piao, Timothy O'Connor, Karl Horning, John Mosher, Richard C Burgess, William Bingaman, Dileep R Nair

Epilepsy research 103 ( 1 ) 73 - 82 2013.01 [International journal]

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 PubMed

Surgically proven coexistence of focal and generalized epilepsy: a case report.

Rei Enatsu, Elaine Wyllie, Prakash Kotagal, William Bingaman

Epilepsy & behavior : E&B 26 ( 1 ) 61 - 3 2013.01 [International journal]

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 PubMed

Structural concept of intracranial cavernous angioma for the surgical treatment.

Rei Enatsu, Masato Matsumoto, Minoru Asahi, Osamu Hirai

Chinese medical journal 126 ( 24 ) 4812 - 4812 2013 [International journal]

PubMed

Magnetoencephalography in fronto-parietal opercular epilepsy.

Yosuke Kakisaka, Masaki Iwasaki, Andreas V Alexopoulos, Rei Enatsu, Kazutaka Jin, Zhong I Wang, John C Mosher, Anne-Sophie Dubarry, Dileep R Nair, Richard C Burgess

Epilepsy research 102 ( 1-2 ) 71 - 7 2012.11 [International journal]

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 PubMed

Meningioma-related dural arteriovenous fistula fed via a vascular tumor bed: a case report and literature review.

Rei Enatsu, Minoru Asahi, Masato Matsumoto, Osamu Hirai

Clinical neurology and neurosurgery 114 ( 7 ) 1010 - 3 2012.09 [International journal]

DOI PubMed

前頭頭頂部前頭葉てんかんにおける脳磁図(Magnetoencephalography in Fronto-Parietal Opercular Epilepsy)

Kakisaka Yosuke, 岩崎真樹, 神一敬, 江夏怜, Burgess Richard, 呉繁夫, 中里信和

てんかん研究 ( (一社)日本てんかん学会 ) 30 ( 2 ) 313 - 313 2012.09

Correlations between ictal propagation and response to electrical cortical stimulation: a cortico-cortical evoked potential study.

Rei Enatsu, Kazutaka Jin, Sherif Elwan, Yuichi Kubota, Zhe Piao, Timothy O'Connor, Karl Horning, Richard C Burgess, William Bingaman, Dileep R Nair

Epilepsy research 101 ( 1-2 ) 76 - 87 2012.08 [International journal]

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 PubMed

Complementary effect of surgical resection and responsive brain stimulation in the treatment of bitemporal lobe epilepsy: a case report.

Rei Enatsu, Andreas Alexopoulos, William Bingaman, Dileep Nair

Epilepsy & behavior : E&B 24 ( 4 ) 513 - 6 2012.08 [International journal]

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 PubMed

Clinical evidence for the utility of movement compensation algorithm in magnetoencephalography: successful localization during focal seizure.

Yosuke Kakisaka, Zhong I Wang, John C Mosher, Anne-Sophie Dubarry, Andreas V Alexopoulos, Rei Enatsu, Prakash Kotagal, Richard C Burgess

Epilepsy research 101 ( 1-2 ) 191 - 6 2012.08 [International journal]

DOI PubMed

Pituitary apoplexy presenting atypical time course of ophthalmic symptoms.

Rei Enatsu, Minoru Asahi, Masato Matsumoto, Osamu Hirai

The Tohoku journal of experimental medicine 227 ( 1 ) 59 - 61 2012.05 [Domestic journal]

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.

PubMed

Prognostic factors of motor recovery after stereotactic evacuation of intracerebral hematoma.

Rei Enatsu, Minoru Asahi, Masato Matsumoto, Osamu Hirai

The Tohoku journal of experimental medicine 227 ( 1 ) 63 - 7 2012.05 [Domestic journal]

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.

PubMed

Cortical excitability varies upon ictal onset patterns in neocortical epilepsy: a cortico-cortical evoked potential study.

Rei Enatsu, Zhe Piao, Timothy O'Connor, Karl Horning, John Mosher, Richard Burgess, William Bingaman, Dileep Nair

Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology 123 ( 2 ) 252 - 60 2012.02 [International journal]

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 PubMed

Ictal singing due to left frontal lobe epilepsy: a case report and review of the literature.

Rei Enatsu, Stephen Hantus, Jorge Gonzalez-Martinez, Norman So

Epilepsy & behavior : E&B 22 ( 2 ) 404 - 6 2011.10 [International journal]

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 PubMed

　 PREV - NEXT 　

<ENATSU Rei>

Papers - ENATSU Rei