Faculty Profiles - AKIYAMA Tomoyuki

Cortical Gamma-Oscillations Modulated by Auditory-Motor Tasks-Intracranial Recording in Patients With Epilepsy Reviewed

Tetsuro Nagasawa, Robert Rothermel, Csaba Juhasz, Miho Fukuda, Masaaki Nishida, Tomoyuki Akiyama, Sandeep Sood, Eishi Asano

HUMAN BRAIN MAPPING 31 ( 11 ) 1627 - 1642 2010.11

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Human activities often involve hand-motor responses following external auditory verbal commands It has been believed that hand movements are predominantly driven by the contralateral primary sensorimotor cortex, whereas auditory-verbal information is processed in both superior temporal gyn. It remains unknown whether cortical activation in the superior temporal gyrus during an auditory motor task is affected by laterality of hand-motor responses Here, event-related gamma-oscillations were intracranially recorded as quantitative measures of cortical activation; we determined how cortical structures were activated by auditory-cued movement Using each hand in 15 patients with focal epilepsy. Auditory-verbal stimuli elicited augmentation of gamma-oscillations in a posterior portion of the superior temporal gyrus, whereas hand-motor responses elicited gamma-augmentation in the pre- and postcentral gyn. The magnitudes of such gamma-augmentation in the superior temporal, precentral, and postcentral gyn were significantly larger when the hand contralateral to the recorded hemisphere was required to be used for motor responses, compared with when the ipsilateral hand was. The superior temporal gyrus in each hemisphere might play a greater pivotal role when the contralateral hand needs to be used for motor responses, compared with when the ipsilateral hand does. Hum Brain Mapp 31 1627-1642, 2010. (C) 2010 Wiley-Liss, Inc.

DOI： 10.1002/hbm.20963

Rapid oscillatory activity in delta brushes of premature and term neonatal EEG Reviewed

Derrick W. S. Chan, Madoka Yamazaki, Tomoyuki Akiyama, Bill Chu, Elizabeth J. Donner, Hiroshi Otsubo

BRAIN & DEVELOPMENT 32 ( 6 ) 482 - 486 2010.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We compared frequency and power of neonatal EEG delta brush rapid oscillatory activity (ROA) using multiple band frequency analysis (MBFA) in three groups; pre-term (PT, post-conceptional age 33-35.6 weeks, n = 5); full-term (FT, 39.4-40.6 weeks, n = 5) and pre-term or full-term with phenobarbital exposure (PB, n = 5). Mean number of delta brushes analyzed was 29.4 (range 26-47) in PT, 20.8 (14-33) in FT and 20 (7-37) in PB. Mean frequency +/- standard deviation (s.d.) was 16.9 +/- 2.1 Hz (range 15-20 Hz) in PT, 17.3 +/- 1.9 Hz (15-20 Hz) in FT and 16.1 +/- 1.6 Hz (14-19 Hz) in PB. Mean power +/- s.d. was 22.9 +/- 6.2 mu V(2) (range 16-39 mu V(2)) in PT, 11.9 +/- 4.1 mu V(2) (7-19 mu V(2)) in FT and 17.1 +/- 6.2 mu V(2) (9-26 mu V(2)) in PB. Power was significantly higher in PT than FT (p < 0.005). Power after merging PB into respective PT (PT', n = 8) and FT (FT', n = 7) groups, remained significantly higher in PT' (mean +/- s.d. 21.8 +/- 7.4 mu V(2)) than FT' (11.4 +/- 3.6 mu V(2)) (p < 0.05). We characterise ROA in delta brushes in maturing neonates using MBFA, which may provide additional information for assessing future seizure recurrence and epilepsy risk. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.braindev.2009.07.006

[Antiepileptic drugs in North America]. Reviewed

Akiyama T, Otsubo H

Brain and nerve = Shinkei kenkyu no shinpo 62 ( 5 ) 519 - 526 2010.5

What is the point of specifying Panayiotopoulos syndrome from a practical point of view? Reviewed

Eishi Asano, Tomoyuki Akiyama

BRAIN & DEVELOPMENT 32 ( 1 ) 2 - 3 2010.1

Localization of epileptic foci in children with intractable epilepsy secondary to multiple cortical tubers by using synthetic aperture magnetometry kurtosis Clinical article Reviewed

Ichiro Sugiyama, Katsumi Imai, Yu Yamaguchi, Ayako Ochi, Yoko Akizuki, Cristina Go, Tomoyuki Akiyama, O. Carter Snead, Tames T. Rutka, James M. Drake, Elysa Widjaja, Sylvester H. Chuang, Doug Cheyne, Hiroshi Otsubo

JOURNAL OF NEUROSURGERY-PEDIATRICS 4 ( 6 ) 515 - 522 2009.12

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC NEUROLOGICAL SURGEONS

Object. Magnetoencephalography (MEG) has been typically used to localize epileptic activity by modeling interictal activity as equivalent current dipoles (ECDs). Synthetic aperture magnetometry (SAM) is a recently developed adaptive spatial filtering algorithm for MEG that provides some advantages over the ECD approach. The SAM-kurtosis algorithm (also known as SAM[g2]) additionally provides automated temporal detection of spike sources by using excess kurtosis value (steepness of epileptic spike on virtual sensors). To evaluate the efficacy of the SAM(g2) method, the authors applied it to readings obtained in children with intractable epilepsy secondary to tuberous sclerosis complex (TSC), and compared them to localizations obtained with ECDs.
Methods. The authors studied 13 children with TSC (7 girls) whose ages ranged from 13 months to 16.3 years (mean 7.3 years). Video electroencephalography, MR imaging, and MEG studies were analyzed. A single ECD model was applied to localize ECD clusters. The SAM(g2) value was calculated at each SAM(g2) virtual voxel in the patient's MR imaging-defined brain volume. The authors defined the epileptic voxels of SAM(g2) (evSAM[g2]) as those with local peak kurtosis values higher than half of the maximum. A clustering of ECDs had to contain a 6 ECDs within 1 cm of each other, and a grouping of evSAM(g2)s had to contain a 3 evSAM(g2)s within 1 cm of each other. The authors then compared both ECD clusters and evSAM(g2) groups with the resection area and correlated these data with seizure outcome.
Results. Seizures started when patients were between 6 weeks and 8 years of age (median 6 months), and became intractable secondary to multiple tubers in all cases. Ictal onset on scalp video electroencephalography was lateralized in 8 patients (62%). The MEG studies showed multiple ECD clusters in 7 patients (54%). The SAM(g2) method showed multiple groups of epileptic voxels in 8 patients (62%). Colocalization of grouped evSAM(g2) with ECD clusters ranged from 20 to 100%, with a mean of 82%. Eight patients underwent resection of single (1 patient) and multiple (7 patients) lobes, with 6 patients achieving freedom from seizures. Of 8 patients who underwent surgery, in 7 the resection area covered ECD clusters and grouped evSAM(g2)s. In the remaining patient the resection area partially included the ECD cluster and grouped evSAM(g2)s. Six of the 7 patients became seizure free.
Conclusions. The combination of SAM(g2) and ECD analyses succeeded in localizing the complex epileptic zones in children with TSC who had intractable epilepsy secondary to multiple cortical tubers. For the subset of children with TSC who present with early-onset and nonlateralized seizures, MEG studies in which SAM(g2) and ECD are used might identify suitable candidates for resection to control seizures. (DOI: 10.3171/2009.7.PEDS09198)

DOI： 10.3171/2009.7.PEDS09198

High-frequency oscillations of ictal muscle activity and epileptogenic discharges on intracranial EEG in a temporal lobe epilepsy patient Reviewed

Hiroshi Otsubo, Ayako Ochi, Katsumi Imai, Tomoyuki Akiyama, Ayataka Fujimoto, Cristina Go, Peter Dirks, Elizabeth J. Donner

CLINICAL NEUROPHYSIOLOGY 119 ( 4 ) 862 - 868 2008.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER IRELAND LTD

Objective: During seizures, intracranial EEG electrodes can record ictal muscle movements. Our purpose was to differentiate the high-frequency oscillations (HFOs) of extracranial muscle contractions from those of intracranial epileptogenic discharges.
Methods: Using intracranial video-EEG (IVEEG), we recorded seizures in a 17-year-old boy with left mesial-temporal lobe epilepsy. We used multiple band frequency analysis (MBFA) to differentiate extracranial HFOs of craniofacial muscle activities from intracranial HFOs recorded ictally and interictally.
Results: During I I seizures, IVEEG showed low-amplitude fast waves (similar to 60 Hz) starting at the left mesial-temporal electrodes. Ictal facial grimacing projected low-amplitude (similar to 20 mu V) fast waves (similar to 160 Hz) on inferior lateral-temporal electrodes. Interictal chewing projected medium-amplitude (similar to 100 mu V) fast waves (similar to 140 Hz) correlating to mouth movements. MBFA topographic power spectrograms revealed a sustained, consistent ictal fast-frequency band from electrodes in the seizure-onset zone and randomly scattered HFOs without a specific frequency band from ictal and interictal extracranial muscle contractions.
Conclusions: MBFA power spectrograms differentiated randomly scattered muscle HFOs without a specific frequency band at electrodes close to temporal muscles from ictal epileptic HFOs with a sustained, fast-frequency band in the seizure-onset zone.
Significance: The pattern and distribution of frequency power spectrograms of extracranial HFOs differ from those of intracranial HFOs. (c) 2008 Published by Elsevier Ireland Ltd. on behalf of International Federation of Clinical Neurophysiology.

DOI： 10.1016/j.clinph.2007.12.014

Epileptic spasms in older pediatric patients: MEG and ictal high-frequency oscillations suggest focal-onset seizures in a subset of epileptic spasms Reviewed

Rajesh RamachandranNair, Ayako Ochi, Katsumi Imai, Mony Benifla, Tomoyuki Akiyama, Stephanie Holowka, James T. Rutka, O. Carter Snead, Hiroshi Otsubo

EPILEPSY RESEARCH 78 ( 2-3 ) 216 - 224 2008.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Objectives: To elucidate the pathophysiology of intractable epileptic spasms in older children by describing the interictal. magnetoencephalography spike sources (MEGSSs), intracranial EEG ictal-onset zones (IOZs) and their ictal high-frequency oscillations (HFOs) and surgical outcomes.
Methods: We studied five patients (4.5-14 years) who underwent surgery following intracranial video-EEG (VEEG) monitoring. We analyzed clinical profiles, MRIs, scalp and intracranial. VEEGs, and MEGSSs. We localized ictal. HFOs using a sampling rate of 1000 Hz and multiple band frequency analysis (MBFA).
Results: Seizure onset ranged from 0.4 to 8 years. Three patients presented with asymmetrical spasms. Interictal scalp VEEG recorded predominantly unilateral epileptiform discharges in four; generalized and multifocal in one. Ictal. scalp VEEG showed generalized high-amplitude slow waves with superimposed fast waves in four patients; hemispheric electrodecremental episodes in one. MRI findings were normal in three, hemispheric polymicrogyria and periventricular heterotopia in one each. All. patients had unilateral MEGSS clusters. Ictal. HFOs, ranging from 150 to 250 Hz, localized over Rolandic and frontal regions in four, with one also having extensive temporo-occipital HFOs. After cortical resection, three patients were seizure free; one had >90% reduction in seizure frequency. One patient experienced residual seizures after resection of the hemispheric ictal HFO region.
Conclusion: Unilateral clusters of MEGSSs overlapped regional IOZs in older patients with epileptic spasms. High spatio-temporal MBFA before and during spasms revealed the regional ictal HFOs. Seizure-free outcomes following resection of zone with MEGSS clusters and ictal HFOs suggested that a subset of epileptic spasms was focal-onset seizures. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.eplepsyres.2007.12.007

Dynamic changes of ictal high-frequency oscillations in neocortical epilepsy: Using multiple band frequency analysis Reviewed

Ayako Ochi, Hiroshi Otsubo, Elizabeth J. Donner, Irene Elliott, Ryoichi Iwata, Takanori Funaki, Yoko Akizuki, Tomoyuki Akiyama, Katsumi Imai, James T. Rutka, O. Carter Snead

EPILEPSIA 48 ( 2 ) 286 - 296 2007.2

Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL PUBLISHING

Purpose: To characterize the spatial and temporal course of ictal high-frequency oscillations (HFOs) recorded by subdural EEG in children with intractable neocortical epilepsy.
Methods: We retrospectively studied nine children (four girls, five boys; 4-17 yr) who presented with intractable extrahippocampal localization-related epilepsy and who underwent extraoperative video subdural EEG (1000 Hz sampling rate) and cortical resection. We performed multiple band frequency analysis (MBFA) to evaluate the frequency, time course, and distribution of ictal HFOs. We compared ictal HFO changes before and after clinical onset and postsurgical seizure outcomes.
Results: Seventy-eight of 79 seizures showed HFOs. We observed wide-band HFOs (similar to 250Hz, similar to 120 electrodes) in six patients either with partial seizures alone (three patients) or with epileptic spasms (three patients). Three patients with partial seizures that secondarily generalized had wide-band HFOs (similar to 170 Hz) before clinical onset and sustained narrow-band HFOs (60-164 Hz) with electrodecremental events after clinical onset (similar to 28 electrodes). In four postoperatively seizure-free patients, more electrodes recorded higher-frequency HFOs inside the resection area than outside before and after clinical seizure onset. In five patients with residual seizures, electrodes recorded more HFOs that were of higher or equal frequency outside the surgical area than inside after clinical onset.
Conclusion: For partial seizures alone and epileptic spasms, more electrodes recorded only wide-band HFOs; for partial seizures that secondarily generalized, fewer electrodes recorded wide-band HFOs, but in these seizures electrodes also recorded subsequent sustained narrow-band ictal HFOs. Resection of those brain regions having electrodes with ictal, higher HFOs resulted in postsurgical seizure-free outcomes.

DOI： 10.1111/j.1528-1167.2007.00923.x

Rivabirin治療を行った亜急性硬化性全脳炎の1例

遠藤文香, 岡牧郎, 秋山倫之, 大塚頌子

脳と発達 39 ( 1 ) 72 - 72 2007.1

内側側頭葉てんかんの小児例の術前評価

井上拓志, 秋山倫之, 岡牧郎, 吉永治美, 大塚頌子

脳と発達 39 ( 1 ) 73 - 73 2007.1

Topographic movie of ictal high-frequency oscillations on the brain surface using subdural EEG in neocortical epilepsy Reviewed

Tomoyuki Akiyama, Hiroshi Otsubo, Ayako Ochi, Elaine Z. Galicia, Shelly K. Weiss, Elizabeth J. Donner, James T. Rutka, O. Carter Snead

EPILEPSIA 47 ( 11 ) 1953 - 1957 2006.11

Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL PUBLISHING

Purpose: To understand the rapid dynamic changes of ictal intracranial high-frequency oscillations (HFOs) in neocortical epilepsy.
Methods: We integrated multiple band frequency analysis and brain-surface topographic maps of HFOs from ictal subdural EEG (SDEEG) recordings. We used SDEEG to record partial seizures consisting of right-arm jerks with secondary generalization in a 17-year-old right-handed girl. We selected 20-s EEG sections that included preclinical seizure recordings. We averaged the HFO power between 60 and 120 Hz for 25 selected electrodes, made topographic maps from these averaged powers, and superimposed the maps on the brain-surface image. We filmed consecutive HFO maps at a 10-ms frame rate.
Results: Before clinical seizure onset, high-power HFOs emerged at the superior portion of the left precentral gyrus, then appeared in the middle of the left postcentral gyrus, and subsequently reverberated between both regions as well as the posterior portion of the left postcentral gyrus. Right-arm extension and facial grimacing started as the HFO power decreased. As generalized tonic-clonic seizures evolved, HFO power increased but remained within the central region.
Conclusions: Topographic movies of intracranial HFOs on the brain surface allow visualization of the dynamic ictal changes in neocortical epilepsy.

DOI： 10.1111/j.1528-1167.2006.00823.x

Proposed diagnostic scheme for the classification of epileptic seizures and epilepsies (ILAE, 2001): Proposal from Japan Epilepsy Society Reviewed

Kazuie Iinuma, Kiyoshi Morimoto, Tomoyuki Akiyama, Akio Ikeda, Mana Kurihara

EPILEPSIA 47 ( 9 ) 1588 - 1589 2006.9

The mildest known case of Fukuyama-type congenital muscular dystrophy Reviewed

Tomoyuki Akiyama, Yoko Ohtsuka, Tsutomu Takata, Junri Hattori, Yukiko Kawakita, Kayoko Saito

BRAIN & DEVELOPMENT 28 ( 8 ) 537 - 540 2006.9

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We present a 14-year-old boy with Fukuyama-type congenital muscular dystrophy (FCMD) who shows the mildest muscle weakness ever reported with this affliction and exceptionally mild mental retardation, but who has intractable epilepsy. Magnetic resonance imaging showed the typical abnormalities of FCMD. Molecular genetic analyses revealed a 3 kb insertion mutation in the fukutin gene heterozygously. We could find no mutation in the coding region of the fukutin gene in the chromosome without a 3 kb insertion. The most probable mechanism of clinical manifestation in this patient could be either a mutation in the noncoding regions of the fukutin gene on the chromosome without the ancestral founder haplotype of FCMD, or an error in the process of transcription or translation. Another possibility is the abnormalities in other genes involved in the glycosylation of alpha-dystroglycan, such as Fukutin-related protein and LARGE genes. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.braindev.2006.02.003

A population-based survey of childhood epilepsy in Okayama Prefecture, Japan: Reclassification by a newly proposed diagnostic scheme of epilepsies in 2001 Reviewed

Tomoyuki Akiyama, Katsuhiro Kobayashi, Tatsuya Ogino, Harumi Yoshinaga, Eiji Oka, Makio Oka, Minako Ito, Yoko Ohtsuka

EPILEPSY RESEARCH 70 S34 - S40 2006.8

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The purpose of this study is to clarify the usefulness and problems of the newly proposed classification of epilepsies (International League Against Epilepsy: ILAE, 2001) in the epidemiological studies of epilepsy.
We previously conducted an epidemiological study in Okayama Prefecture, Japan, in 1999, using the ILAE 1989 classification. Among 250,997 children under 13 years of age, 2220 epileptic patients were ascertained. In this study, we reclassified them according to the ILAE 2001 classification, focusing on axes 2 (seizure types) and 3 (syndromes).
We were able to classify 1803 (95.0%) seizure types out of 1899 with detailed clinical information. In focal seizures, the most common were secondarily generalized seizures (88.6%), which generally do not represent a unique anatomic substrate. In generalized seizures, topic-clonic seizures (40.7%) and spasms (21.0%) were the most common. We identified only 269 (12.1%) patients with specific epilepsy syndromes out of the 2220. We classified 1761 patients without specific syndromic diagnoses only by axis 2, but the new concept of epileptic seizure types, representing a unique pathophysiologic mechanism and anatomic substrate, was not very meaningful in most cases, even in those with focal seizures. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.eplepsyres.2005.11.017

臨床脳波を基礎から学ぶ人のために正常脳波の年齢的変化小児(新生児を含む)

小児神経留学ネットワーク活動報告

山本俊至, 加藤光広, 作田亮一, 新島新一, 友田明美, 秋山倫之, 福水道郎, 高橋和俊, 稲葉雄二, 福山幸夫

脳と発達 38 ( Suppl. ) S312 - S312 2006.5

大塚頌子, 秋山倫之, 岡牧郎

臨床神経生理学 34 ( 2 ) 97 - 106 2006.4

EEG and seizure exacerbation induced by carbamazepine in Panayiotopoulos syndrome Reviewed

K Kikumoto, H Yoshinaga, M Oka, M Ito, F Endoh, T Akiyama, Y Ohtsuka

EPILEPTIC DISORDERS 8 ( 1 ) 53 - 56 2006.3

Language：English Publishing type：Research paper (scientific journal) Publisher：JOHN LIBBEY EUROTEXT LTD

We report on a 4-year 8-month-old boy with Panayiotopoulos syndrome who showed atypical evolution with newly developed absence seizures and EEG exacerbation induced by carbamazepine. Soon after the introduction of carbamazepine, EEGs began to worsen, and finally absence seizures and myoclonic seizures appeared. Immediately after we discontinued carbamazepine, the seizures disappeared and the EEG improved. Carbamazepine may induce unusual electroclinical features, electrophysiologically explained by bilateral synchrony. This case provides more evidence of the close links between Panayiotopoulos syndrome and benign childhood epilepsy with centrotemporal spikes.

Partial seizures triggering infantile spasms in the presence of a basal ganglia glioma Reviewed

R RamachandranNair, A Ochi, T Akiyama, DJ Buckley, TB Soman, SK Weiss, H Otsubo

EPILEPTIC DISORDERS 7 ( 4 ) 378 - 382 2005.12

Language：English Publishing type：Research paper (scientific journal) Publisher：JOHN LIBBEY EUROTEXT LTD

Infantile spasms associated with brain tumors have been reported. A focal cortical lesion can induce infantile spasms by triggering the brainstem and basal ganglia in this vulnerable age group. We report the case of a female infant with a low-grade glioma in the right basal ganglia, spreading to the cortical area. She presented at the age of five months with left hemiparesis and partial seizures. She developed infantile spasms at the age of 12 months. This is the first video clip report of partial seizures triggering symmetrical spasms in series, secondary to a basal ganglia glioma extending to the cortex.

Focal cortical high-frequency oscillations trigger epileptic spasms: Confirmation by digital video subdural EEG Reviewed

T Akiyama, H Otsubo, A Ochi, T Ishiguro, G Kadokura, R RamachandranNair, SK Weiss, JT Rutka, O Snead

CLINICAL NEUROPHYSIOLOGY 116 ( 12 ) 2819 - 2825 2005.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER IRELAND LTD

Objective: To localize high-frequency oscillations (HFOs) on the cortex during epileptic spasms using video subdural EEG and Multiple Band Frequency Analysis (MBFA).
Methods: Using video subdural EEG sampled at 1 kHz, we studied a 14-year-old boy with asymmetric epileptic spasms of possible left frontal origin. We identified HFOs, then analyzed and localized their distributions by MBFA. We correlated HFO distribution to clinical spasm intensity.
Results: Ictal subdural EEG recorded HFOs at 60-150 Hz lasting 0.3-4 s. MBFA showed extensive but noncontiguous distribution of HFOs predominantly over the left frontal and temporal regions. HFOs began and became quasiperiodic before manifestation of clinical spasms. As clinical spasms intensified, HFOs persisted in regions where they initiated subclinically but were of higher frequency and greater power than HFOs in other regions. We performed cortical resections over the left frontal and temporal regions with predominant HFOs. Six months after surgery, the patient remained seizure free.
Conclusions: HFOs were present over the ictal onset zone during epileptic spasms. Periodic spasms in this patient had the characteristics of partial seizures.
Significance: We show that HFOs occurred over the cerebral cortex during epileptic spasms, and we suggest that these focal cortical HFOs triggered the spasms. (c) 2005 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.clinph.2005.08.029