Search

Objective: Giant somatosensory evoked potentials (SEPs) are observed in patients with cortical myoclonus. Short-latency components (SLC), are regarded as evoked epileptic activities or paroxysmal depolarization shifts (PDSs). This study aimed to reveal the electrophysiological significance of the middle-latency component (MLC) P50 of the SEPs., Methods: Twenty-two patients with cortical myoclonus having giant SEPs (patient group) and 15 healthy controls were included in this study. Waveform changes in SEPs before and after perampanel (PER) treatment were evaluated in the patient group. The wide range, time-frequency properties underlying the waveforms were compared between the groups., Results: After PER treatment, SLC was prolonged and positively correlated with PER concentration, whereas MLC showed no correlation with PER concentration. Time-frequency analysis showed a power increase (156 Hz in all patients, 624 Hz in benign adult familial myoclonus epilepsy patients) underlying SLC and a power decrease (156 Hz, 624 Hz) underlying MLC in the patient group., Conclusions: The high-frequency power increase in SLCs and decrease in MLCs clearly reflected PDS and subsequent hyperpolarization, respectively. This relationship was similar to that of interictal epileptiform discharges, suggesting that giant SEPs evoke epileptic complexes of excitatory and inhibitory components., Significance: MLCs of giant SEPs reflected inhibitory components., (Copyright © 2024. Published by Elsevier B.V.)

Objective: To investigate the subjective phenomenon and the neural underpinnings of tics compared with voluntary movements in patients with tic disorders., Methods: We recorded electroencephalographic and electromyographic data while subjects completed a Libet clock paradigm. Patients and healthy volunteers reported the times of W (willing to move) and M (movement occurrence) while performing voluntary movements. This was repeated only for the patients for the tics., Results: In the patients, W and M times preceding voluntary movements and tics did not significantly differ from voluntary movements of healthy volunteers. The Bereitschaftspotentials in the patients were similar to healthy volunteers. Tics were only assessable for 7 patients due to artifacts. Two subjects did not show Bereitschaftspotentials, and they reported the lowest levels of tic voluntariness. 5 subjects did not show beta band event-related desynchronization before tics., Conclusions: For patients, the sense of volition for tics is similar to that of their voluntary movements which is similar to normal. Patients showed dissociations between the Bereitschaftspotential and beta desynchronization for tics, with 5/7 showing normal Bereitschaftspotentials and 2/7 showing desynchronization. The absence of desynchronization may suggest attempts to suppress tics., Significance: This physiology shows a difference for most tics compared with normal movements., (Published by Elsevier B.V.)

Objective: To determine clinically ictal direct current (DC) shifts that can be identified by a time constant (TC) of 2 s and to delineate different types of DC shifts by different attenuation patterns between TC of 10 s and 2 s., Methods: Twenty-one patients who underwent subdural electrode implantation for epilepsy surgery were investigated. For habitual seizures, we compared (1) the peak amplitude and (2) peak latency of the earliest ictal DC shifts between TC of 10 s and 2 s. Cluster and logistic regression analyses were performed based on the attenuation rate of amplitude and peak latency with TC 10 s., Results: Ictal DC shifts in 120 seizures were analyzed; 89.1% of which were appropriately depicted even by a TC of 2 s. Cluster and logistic regression analyses revealed two types of ictal DC shift. Namely, a rapid development pattern was defined as the ictal DC shifts with a shorter peak latency and they also showed smaller attenuation rate of amplitude (73/120 seizures). Slow development pattern was defined as the ictal DC shifts with crosscurrent of a rapid development pattern, i.e., a longer peak latency and larger attenuation rate of amplitude (47/120 seizures). Focal cortical dysplasia (FCD) 1A tended to show a rapid development pattern (22/29 seizures) and FCD2A tended to show a slow development pattern (13 /18 seizures), indicating there might be some correlations between two types of ictal DC shift and certain pathologies., Conclusions: Ictal DC shifts, especially rapid development pattern, can be recorded and identified by the AC amplifiers of TC of 2 s which is widely used in many institutes compared to that of TC of 10 s. Two types of ictal DC shifts were identified with possibility of corresponding pathology., Significance: Ictal DC shifts can be distinguished by their attenuation patterns., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objectives: This study investigated neuronal sources of slow cortical potentials (SCPs) evoked during vagus nerve stimulation (VNS) in patients with epilepsy who underwent routine electroencephalography (EEG) after implantation of the device., Materials and Methods: We analyzed routine clinical EEG from 24 patients. There were 5 to 26 trains of VNS during EEG. To extract SCPs from the EEG, a high-frequency filter of 0.2 Hz was applied. These EEG epochs were averaged and used for source analyses. The averaged waveforms for each patient and their grand average were subjected to multidipole analysis. Patients with at least 50% seizure frequency reduction were considered responders. Findings from EEG analysis dipole were compared with VNS responses., Results: VNS-induced focal SCPs whose dipoles were estimated to be located in several cortical areas including the medial prefrontal cortex, postcentral gyrus, and insula, with a significantly higher frequency in patients with a good VNS response than in those with a poor response., Conclusions: This study suggested that some VNS-induced SCPs originating from the so-called vagus afferent network are related to the suppression of epileptic seizures., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Physiological gamma and ripple activities may be linked to neurocognitive functions. This study investigated the relationship between development and non-epileptic, probably physiological, fast (40-200 Hz) oscillations (FOs) including gamma (40 - 80 Hz) and ripple (80 - 200 Hz) oscillations in scalp EEG in children with neurodevelopmental disorders., Methods: Participants were 124 children with autism spectrum disorder (ASD) and/or attention deficit/hyperactivity disorder (ADHD). Gamma and ripple oscillations were explored from 60-second-long sleep EEG data in each subject using a semi-automatic detection tool supplemented with visual confirmation and time-frequency analysis., Results: Gamma and ripple oscillations were detected in 25 (20.2%) and 22 (17.7%) children, respectively. The observation of one or more occurrence(s) of ripple oscillations, but not gamma oscillations, was significantly related to lower age at EEG recording (odds ratio, OR: 0.727 [95% confidence interval, CI: 0.568-0.929]), higher intelligence/developmental quotient (OR: 1.041, 95% CI: 1.002-1.082), and lack of a diagnosis with ADHD (OR: 0.191, 95% CI: 0.039 - 0.937) according to a binominal logistic regression analysis that included diagnosis with ASD, sex, history of perinatal complications, history of febrile seizures, and use of a sedative agent for the EEG recording as the other non-significant parameters. Diagnostic group was not related to frequency or power of spectral peaks of FOs., Conclusion: The production of non-epileptic scalp ripples was confirmed to be associated with brain development and function/dysfunction in childhood. Further investigation is necessary to interpret all of the information on higher brain functions that may be embedded in scalp FOs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Clinical neurophysiology studies can contribute important information about the physiology of human movement and the pathophysiology and diagnosis of different movement disorders. Some techniques can be accomplished in a routine clinical neurophysiology laboratory and others require some special equipment. This review, initiating a series of articles on this topic, focuses on the methods and techniques. The methods reviewed include EMG, EEG, MEG, evoked potentials, coherence, accelerometry, posturography (balance), gait, and sleep studies. Functional MRI (fMRI) is also reviewed as a physiological method that can be used independently or together with other methods. A few applications to patients with movement disorders are discussed as examples, but the detailed applications will be the subject of other articles., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Mark Hallett is an inventor of patents held by NIH for an immunotoxin for the treatment of focal movement disorders and the H-coil for magnetic stimulation; in relation to the latter, he has received license fee payments from the NIH (from Brainsway). He is on the Medical Advisory Boards of CALA Health and Brainsway. He has research grants from Allergan for studies of methods to inject botulinum toxins, Medtronic, Inc. for a study of DBS for dystonia, and CALA Health for studies of a device to suppress tremor. Rodger Elble has served as a consultant for Applied Therapeutics, Cadent, Cavion, Cydan, Five Microns, Jazz, Merz, Neurocrine Biosciences, Osmotica, Praxis Precision Medicines, and Sage in the design and execution of clinical trials for essential tremor. He serves on advisory boards for the International Essential Tremor Foundation and the Neuroscience Research Foundation of Kiwanis International, Illinois-Eastern Iowa District. Fay B. Horak has a significant financial interest in ADPM Wearable Technology, an ERT company that may have a commercial interest in wearable technology. This potential conflict has been reviewed and managed by OHSU. Dr. Horak also consults for Neuropore, Sanofi, and Takeda. Lourdes M. DelRosso, Raffaele Ferri, Stephane Lehericy, Martina Mancini, Masao Matsuhashi, Riki Matsumoto, Muthuraman Muthuraman, Jan Raethjen, Hiroshi Shibasaki: none]., (Published by Elsevier B.V.)

Objective: Cortico-cortical evoked potential (CCEP) by single-pulse electrical stimulation (SPES) is useful to investigate effective connectivity and cortical excitability. We aimed to clarify the safety of CCEPs., Methods: We retrospectively analyzed 29 consecutive patients with intractable partial epilepsy undergoing chronic subdural grid implantation and CCEP recording. Repetitive SPES (1 Hz) was systematically applied to a pair of adjacent electrodes over almost all electrodes. We evaluated the incidences of afterdischarges (ADs) and clinical seizures., Results: Out of 1283 electrode pairs, ADs and clinical seizures were observed in 12 and 5 pairs (0.94% and 0.39%, per electrode pair) in 7 and 3 patients (23.3% and 10.0%, per patient), respectively. Of the 18-82 pairs per patient, ADs and clinical seizures were induced in 0-4 and 0-3 pairs, respectively. Stimulating 4 SOZ (seizure onset zone) (2.5%) and 8 non-SOZ pairs (0.75%) resulted in ADs. We observed clinical seizures in stimulating 4 SOZ (2.5%) and 1 non-SOZ pair (0.09%). The incidence of clinical seizures varied significantly between SOZ and non-SOZ stimulations (p = 0.001), while the difference in AD incidence tended towards significance (p = 0.058)., Conclusion: Although caution should be taken in stimulating SOZ, CCEP is a safe procedure for presurgical evaluation., Significance: CCEP is safe under the established protocol., Competing Interests: Declaration of Competing Interest Department of Epilepsy, Movement Disorders and Physiology (Kyoto University Graduate School of Medicine) is the Industry-Academic Collaboration Courses, supported by Eisai Co., Ltd., NIHON KOHDEN CORPORATION, Otsuka Pharmaceutical Co., and UCB Japan Co., Ltd., (Copyright © 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

EEG findings in advanced Gerstmann-Sträussler-Scheinker syndrome (GSS) are shown. A 56-year-old woman developed GSS symptoms and was diagnosed as having GSS with the P102L mutation at age 58. During the early stage, there were no significant EEG findings. Her clinical condition worsened and she developed akinetic mutism at age 62. The patient died of pneumonia at age 65. EEGs were recorded annually from age 61 to 65. Bilateral independent periodic discharges (BIPDs) in both temporal areas appeared at age 64. No clinical seizures were noticed. MEG showed the sharp waves of BIPDs originated independently in each temporal lobe. Other causes of BIPDs were absent., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: In Japan, microsurgical skill development and a system to transfer patients to an appropriate hospital for upper extremity amputation have been promoted; however, information about trends of replantation is limited. Therefore, the aim of this study was to clarify the trends in the treatment for upper extremity amputation using the Japan Trauma Data Bank (JTDB)., Methods: Data derived from JTDB (2004-2015) were used to quantify trends in the volume of replantation for upper extremity amputation including finger amputation. Trauma was diagnosed based on the Abbreviated Injury Scale code; a subgroup of patients who underwent replantation was delineated. We investigated patient demographics, infection rate, and characteristics of treating facilities., Results: A total of 1240 patients underwent upper extremity amputation. Among these, 510 (41.1%) underwent replantation, and the rate of replantation did not change over the study period. The average age of patients who underwent or did not undergo replantation was 45.5 and 47.2 years, respectively. The proportion of the patients who were transferred to another hospital for treatment significantly decreased between 2004 (28.5%) and 2015 (16.3%) (P < 0.01). Time taken for transfer from the accident site to hospitals increased. The rate of patients who underwent replantation differed among different hospitals; however, higher-volume hospitals were more likely to perform replantation., Conclusion: The rate of patients transferred to another hospital decreased between 2004 and 2015; however, the rate of patients who underwent replantation remained unchanged. This suggests that the number of patients who were transported directly from the accident site to an appropriate hospital has increased, whereas the indication for care in each hospital remains unchanged. Common criteria for amputations are needed to address the differing rates of replantation among hospitals., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest regarding the publication of this article., (Copyright © 2020 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Introduction: Epilepsy associated with tuberous sclerosis complex (TSC) has very complex clinical characteristics. Scalp electroencephalogram (EEG) fast (40-200 Hz) oscillations (FOs) were recently suggested to indicate epilepsy severity. Epileptic FOs may undergo age-dependent longitudinal change in individual patients, however, and the typical pattern of such change is not yet fully clarified. We therefore investigated the age-related correspondence between clinical courses and FOs in pediatric patients with TSC-associated epilepsy., Subjects and Methods: FOs were semi-automatically detected from scalp sleep EEG data recorded from 23 children (15 boys, 8 girls; initial data obtained at <10 years of age) with TSC-associated epilepsy., Results: The number of FOs per patient that were associated with spikes was significantly greater than that of FOs unassociated with spikes (median 145 and 5, respectively; p = 0.0001 by the Wilcoxon signed-rank test). In the eight patients who had West syndrome (WS) in infancy, FOs associated with spikes were abundant during the WS period prior to adrenocorticotropic hormone therapy, with significantly greater numbers of FOs compared to the post-WS period (median 242 and 0, respectively; p = 0.0078). As there was no such time-dependent difference regarding FOs unassociated with spikes, FOs associated with spikes were identified as epileptic. The detected FOs included both gamma and ripple oscillations with no consistent age-dependent shifts in dominant frequency. There were no apparent age-related changes in FO duration., Conclusions: Epileptic scalp FOs are confirmed to correspond to severity of epileptic encephalopathy, particularly in WS, even during the long-term evolutional courses of TSC-associated epilepsy., (Copyright © 2020 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Objective: We aimed to delineate the engagement of cortico-cortical and cortico-subcortical networks in the generation of epileptic spasms (ES) using integrated neurophysiological techniques., Methods: Seventeen-year-old male patient with intractable ES underwent chronic subdural electrode implantation for presurgical evaluation. Networks were evaluated in ictal periods using high-frequency oscillation (HFO) analysis and in interictal periods using magnetoencephalography (MEG) and simultaneous electroencephalography, and functional magnetic resonance imaging (EEG-fMRI). Cortico-cortical evoked potentials (CCEPs) were recorded to trace connections among the networks., Results: Ictal HFO revealed a network comprising multilobar cortical regions (frontal, parietal, and temporal), but sparing the positive motor area. Interictally, MEG and EEG-fMRI revealed spike-and-wave-related activation in these cortical regions. Analysis of CCEPs provided evidence of connectivity within the cortico-cortical network. Additionally, EEG-fMRI results indicate the involvement of subcortical structures, such as bilateral thalamus (predominantly right) and midbrain., Conclusions: In this case study, integrated neurophysiological techniques provided converging evidence for the involvement of a cortico-cortical network (sparing the positive motor area) and a cortico-subcortical network in the generation of ES in the patient., Significance: Cortico-cortical and cortico-subcortical pathways, with the exception of the direct descending corticospinal pathway from the positive motor area, may play important roles in the generation of ES., Competing Interests: Declaration of Competing Interest None of the authors have any conflicts of interest or potential financial interests to disclose. Department of Epilepsy, Movement Disorders and Physiology is the Industry-Academia Collaboration Courses, supported by Eisai Co., Ltd., Nihon Kohden Corporation, Otsuka Pharmaceutical Co., and UCB Japan Co., Ltd. We confirm that we have read the journal's position on issues involving ethical publication and affirm that this report is consistent with those guidelines and all authors have approved the final article., (Copyright © 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: Using interictal epileptiform discharges (IEDs), consisting of spikes and post-spike slow waves (PSSs), and IED-related high-frequency activities (HFAs), we elucidated inhibitory effects of electrical cortical stimulation (ECS) on human epileptic foci., Methods: We recruited 8 patients with intractable focal epilepsy, and 50-Hz ECS was applied to the seizure-onset zone (SOZ) and non-SOZ. Before (5-min) and after (20-min) ECS, we evaluated the number of IED, the amplitudes of spikes and PSSs, spike-related HFA power, and PSS-related low gamma (30-50 Hz) activities., Results: SOZ stimulation significantly decreased the number of IEDs and amplitude of spikes. Spike-related HFA power values in fast ripple (200-300 Hz) and ripple (80-150 Hz) bands were significantly suppressed only by SOZ stimulation in 4 and 3 patients, respectively. Among 4 patients with discrete PSSs, the amplitude ratio of spike/PSS decreased and the PSS-related low gamma activity power increased significantly in 2 patients and marginally in 1 patient., Conclusions: ECS potentially modulates cortical excitability by reducing excitation and increasing inhibition, and monitoring IED-related HFAs may help achieve the optimal effects of ECS., Significance: IED and IED-related HFAs are dynamic, potential surrogate markers for epileptic excitability during the interictal period., Competing Interests: Declaration of Competing Interest None of the authors have any conflicts of interest or potential financial interests to disclose. Department of Epilepsy, Movement Disorders and Physiology is the Industry-Academia Collaboration Courses, supported by Eisai Co., Ltd., Nihon Kohden Corporation, Otsuka Pharmaceutical Co., and UCB Japan Co., Ltd. We confirm that we have read the journal’s position on issues involving ethical publication and affirm that this report is consistent with those guidelines and all authors have approved the final article., (Copyright © 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

An accurate identification of the epileptogenic zone is essential for patients with intractable epilepsy who are candidates to neurosurgery. EEG recordings can provide predictive biomarkers of the epileptogenic zone. Wide-band EEG makes it possible to record from infraslow (including DC shifts) to high frequency (HFO, over 300 Hz) oscillations for diagnostic purposes in patients with epilepsy. Although the presence of HFOs have been proposed to sign the epileptogenic zone, DC-like recordings demonstrate that DC shifts precede HFOs at seizure onset. This led to the proposal that "ictal active DC shifts" are causally related to seizure onset as opposed to "ictal passive DC shifts". Thus, active DC shifts may constitute predictive biomarkers of the epileptogenic zone in epilepsy. Since DC shift is commonly associated to a rise in extracellular potassium, potassium homeostasis regulated by Kir4.1 channels in astrocytes may play an key role at seizure onset. In addition, we hypothesize that, during the interictal period, the co-occurrence of slow events and interictal HFOs, so-called "Red slow", may also delineate an epileptogenic zone, even if a seizure would not be actually recorded., Competing Interests: Declaration of Competing Interest Department of Epilepsy, Movement Disorders and Physiology is an endowment department, supported with a grant from GlaxoSmithKline K.K., NIHON KOHDEN CORPORATION, Otsuka Pharmaceutical Co., and UCB Japan Co., Ltd.Department of Respiratory Care and Sleep Control Medicine is the department donated from Teijin Pharma Limited, Philips Respironics GK, Fukuda Denshi CO., LTD., and Fukuda Lifetech Keiji CO., LTD., (Copyright © 2020 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.)

It remains unclear whether the rhythmic processes of chewing and gait synchronize during concurrent execution in humans. To evaluate the entrainment of chewing rhythm by gait speed, we measured electromyography from the masseter and tibialis anterior muscles during chewing at a habitual rhythm while walking on a linear treadmill in 12 healthy volunteers. Vertical movement of the head was also measured using an accelerometer. Each 5-min session included gait tasks using a treadmill at three speeds: Auto: the participant's self-selected gait speed, High: Auto × 1.3, and Low: Auto ÷ 1.3. Electromyography from the masseter muscles were also measured during chewing while stationary (Chew-Only). Chewing rhythm during walking was the same as that for head movement, occurring at twice the speed of the walking rhythm, in nine participants (Low), eight participants (Auto), and eight participants (High). For these participants, chewing rhythm in the Auto and High conditions differed significantly from that in the Chew-Only condition. Significant differences in chewing rhythm were also observed among gait speeds　(Low vs. Auto vs. High). Our findings demonstrate that entrainment of habitual chewing rhythm to gait speed is a significant phenomenon, and that the dominant ratio of chewing-walking-head movement rhythms is 2:1:2., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to declare., (Copyright © 2020 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.)

The present study aimed to investigate the long-term effects of gait intervention with transcranial alternating current stimulation (tACS) synchronized with gait cycle frequency on the cortical control of muscle activity during gait, using coherence analyses, in patients after stroke. Eight chronic post-stroke patients participated in a single-blinded crossover study, and 7 patients completed the long-term intervention. Each patient received tACS over the primary motor cortex foot area on the affected side, which was synchronized with individual gait cycle frequency, and sham stimulation during treadmill gait in a random order. Electrical neuromuscular stimulation was used to assist the paretic ankle movement in both conditions. After gait intervention with tACS, beta band (15-35 Hz) coherence, which is considered to have a cortical origin, significantly increased in the paretic tibialis anterior (TA) muscle during 6-min of over-ground gait. The change in beta band coherence in the paretic TA muscle was positively correlated with the change in gait distance. These results indicate that gait intervention with tACS synchronized with gait cycle frequency may induce gait-specific plasticity that modulates the common neural drive to the TA motoneurons on the paretic side during gait and leads to changes in gait function in patients after stroke., Competing Interests: Declarations of Competing Interest The Department of Epilepsy, Movement Disorders and Physiology is an Industry-Academia Collaboration Course supported by Grants from Eisai Company, NIHON KOHDEN CORPORATION, Otsuka Pharmaceutical Co., and UCB Japan Co., Ltd., (Copyright © 2019 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.)

Although specific brain regions are important for regularly patterned limb movements, the rhythm generation system that governs bipedal locomotion in humans is not thoroughly understood. We investigated whether rhythmic transcranial brain stimulation over the cerebellum could alter walking rhythm. Fourteen healthy subjects performed over-ground walking for 10 min during which they were given, in a random order, transcranial alternating current stimulation (tACS) over the left cerebellum at the approximated frequency of their gait cycle, tACS over the skin of the scalp, and during sham stimulation. Cerebellar tACS showed a significant entrainment of gait rhythm compared with the control conditions. When the direction of the tACS currents was symmetrically inverted, some subjects showed entrainment at an approximately 180° inverted phase, suggesting that gait modulation is dependent on current orientation. These findings indicate that tACS over cerebellum can modulate gait generation system in cerebellum and become an innovative approach for the recovery of locomotion in patients with gait disturbances caused by CNS disorders., Competing Interests: Declarations of Competing Interest The City University of New York has brain stimulation patents with Marom Bikson as inventor. Marom Bikson has equity in Soterix Medical, Inc. and consults for Boston Scientific. GHK, and Mecta., (Copyright © 2019 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.)

In the present study, we attempted to characterize two characteristic features within the dynamic behavior of wideband electrocorticography data, which were recorded as the brain waves of epilepsy, comprising high-frequency oscillations (HFOs) and interictal epileptic slow (red slow). The results of power spectrum and nonlinear time series analysis indicate that, on one hand, HFOs at epileptic focus are characterized by one-dimensional dynamical systems in ictal onset time segments at an epileptic focus for two patients' datasets; on the other hand, an interictal epileptic slow is characterized by the residue of power spectrum. The results suggest that the degree of freedom of the brain dynamics during epileptic seizure with HFO degenerates to low-dimensional dynamics; hence, the interictal epileptic slow as the precursors of the seizure onset can be detected simply from interictal brain wave data for the dataset of one patient. Therefore, our results are essential to understand the brain dynamics in epilepsy., Competing Interests: Declaration of Competing Interest Masao Matsuhashi and Akio Ikeda: Department of Epilepsy, Movement Disorders and Physiology, Kyoto University is the Industry-Academia Collaboration Courses, supported by Eisai Co., Ltd., Nihon Kohden Corporation, Otsuka Pharmaceutical Co., Ltd. and UCB Japan Co. Ltd., (Copyright © 2019 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.)

Objective: We studied ripple-band (80-200 Hz) high-frequency oscillations in scalp electroencephalogram (EEG) in various pediatric epilepsies featuring sleep-activated spikes, such as epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS) and investigated their characteristics., Methods: The subjects were 94 children with epileptic disorders including idiopathic and non-idiopathic CSWS, benign epilepsy with centrotemporal spikes (BECTS), Panayiotopoulos syndrome, other types of focal epilepsies (oFE), and focal spikes without clinical seizures (Latent). We detected ripple oscillations using a semi-automatic detection tool based on localized power increase., Results: In the idiopathic CSWS Group, the median ratio of ripples per spike in the initial EEG was 5.73, which was significantly higher than those in the BECTS, Panayiotopoulos syndrome, oFE, and Latent Groups (0.39, 0.02, 0.35, 0, respectively, all with p < 0.01). Ripples were particularly frequent at younger ages., Conclusions: This paper is the first to confirm a high ratio of ripples per spike in CSWS in the largest number of patients to date., Significance: The dense generation of ripples, which occurs through a combination of heavy loading of individual spikes with ripples and large numbers of spikes during sleep, characterizes CSWS and might be closely related to the pathophysiology of this epileptic encephalopathy., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: To elucidate the effects of perampanel (PER) on refractory cortical myoclonus for dose, etiology and somatosensory-evoked potential (SEP) findings., Methods: We examined 18 epilepsy patients with seizure and cortical myoclonus. Based on data accumulated before and after PER treatment, correlations among clinical scores in myoclonus and activities of daily life (ADL); early cortical components of SEP; and PER blood concentration, were analyzed., Results: PER (mean dose: 3.2 ± 2.1 mg/day) significantly improved seizures, myoclonus and ADL and significantly decreased the amplitude of and prolonged latency of giant SEP components. The degree of P25 and N33 prolongations (23.8 ± 1.6 to 24.7 ± 1.7 ms and 32.1 ± 4.0 to 33.7 ± 3.4 ms) were significantly correlated with improved ADL score (p = 0.019 and p = 0.025) and blood PER concentration (p = 0.011 and p = 0.025), respectively., Conclusions: Low-dose PER markedly improved myoclonus and ADL in patients with refractory cortical myoclonus. Our results suggest that SEP, particularly P25 latency, can be used as a potential biomarker for assessing the objective effects of PER on intractable cortical myoclonus., Significance: In this study, PER lessened the degree of synchronized discharges in the postsynaptic neurons in the primary motor cortex., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: Neuro-feedback (NFB) training by the self-regulation of slow potentials (SPs) <0.5 Hz recorded from the vertex scalp has been applied for seizure suppression in patients with epilepsy. However, SP is highly susceptible to artifact contamination, such as the galvanic skin response (GSR). This study aimed to evaluate the correlation between SPs recorded from the scalp and intracranial electroencephalography (EEG) by event-related coherence analysis., Methods: The scalp and subdural SPs were simultaneously recorded during NFB training by the DC-EEG machine while undergoing invasive recordings before epilepsy surgery in 10 patients with refractory partial epilepsy. The SPs at the vertex electrode were used as a reference for coherence analysis., Results: The coherence of SPs negatively correlated with the distance between the subdural and scalp electrodes. A significant negative correlation was noted between the linear subdural-scalp electrode distance and the coherence value (r =  - 0.916, p < 0.001)., Conclusion: Scalp-recorded SPs from the vertex area primarily reflect the cortical activity of high lateral convexity., Significance: Our results strongly suggest that SPs in NFB recorded from the vertex scalp electrode is derived from the cortices of high lateral convexity but not from the artifacts, such as GSR., (Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: To assess the feasibility of multi-component electrocorticography (ECoG)-based mapping using "wide-spectrum, intrinsic-brain activities" for identifying the primary sensori-motor area (S1-M1)., Methods: We evaluated 14 epilepsy patients with 1514 subdural electrodes implantation covering the perirolandic cortices at Kyoto University Hospital between 2011 and 2016. We performed multi-component, ECoG-based mapping (band-pass filter, 0.016-300/600 Hz) involving combined analyses of the single components: movement-related cortical potential (<0.5-1 Hz), event-related synchronization (76-200 Hz), and event-related de-synchronization (8-24 Hz) to identify the S1-M1. The feasibility of multi-component mapping was assessed through comparisons with single-component mapping and electrical cortical stimulation (ECS)., Results: Among 54 functional areas evaluation, ECoG-based maps showed significantly higher rate of localization concordances with ECS maps when the three single-component maps were consistent than when those were inconsistent with each other (p < 0.001 in motor, and p = 0.02 in sensory mappings). Multi-component mapping revealed high sensitivity (89-90%) and specificity (94-97%) as compared with ECS., Conclusions: Wide-spectrum, multi-component ECoG-based mapping is feasible, having high sensitivity/specificity relative to ECS., Significance: This safe (non-stimulus) mapping strategy, alternative to ECS, would allow clinicians to rule in/out the possibility of brain function prior to resection surgery., (Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: We aimed to clarify that high frequency activity (HFA) of cortico-cortical evoked potentials (CCEPs), elicited by single pulse electrical stimulation (SPES), reflects cortical excitability., Methods: We recruited 16 patients with refractory partial epilepsy who had chronic subdural electrode implantation for presurgical evaluation. A repetitive SPES was given to (1) the seizure onset zone (SOZ) and (2) the control cortices (non-seizure onset zone: nSOZ). CCEPs were recorded from the neighboring cortices within SOZ and nSOZ. We applied short-time Fourier transform to obtain the induced responses for the timing of early (<50ms after SPES) and late CCEP components and analyzed the logarithmic power change for ripple (<200Hz) and fast ripple (>200Hz) bands., Results: Twenty-one clear CCEPs were recorded for both the SOZ and nSOZ. The HFA power of early CCEPs in SOZ significantly increased compared to that in nSOZ in both frequency bands, particularly in mesial temporal lobe epilepsy (MTLE)., Conclusion: Similar to the features of spontaneous pathological HFOs, the power of stimulus-induced HFAs in SOZ were greater than that outside SOZ, particularly in MTLE., Significance: HFA overriding CCEPs can be a surrogate marker of cortical excitability in epileptic focus., (Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: We investigated whether vagus nerve stimulation (VNS) induces a positive shift of slow cortical potentials (SCPs) in patients with >50% seizure reduction (responders) but not in non-responders., Methods: We analyzed routine clinical electroencephalograms (EEGs) from 24 patients who were undergoing seizure treatment by VNS. The patients were divided into 2 groups by hardware time constant (TC) of EEG: the TC 10-s group (10 patients) and TC 2-s group (14 patients). We compared SCPs at 5 electrodes (Cz and adjacent ones) between the 2 states of VNS: during stimulation and between stimulations. Seizure reduction was independently judged. Correlation between SCP (positivity or not) and seizure reduction (>50% or not) was estimated., Results: In the TC 10-s group, the correlation between SCP and seizure reduction was significant (p<0.05) (i.e., both good results in 4 and both negative results in 5). In TC 2-s group, the correlation between SCP and seizure reduction was not significant (p=0.209)., Conclusions: A positive shift of SCP recorded by using a TC of 10s could be a surrogate marker for VNS response., Significance: SCP could be a biomarker of good responders to VNS., (Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: We describe temporal spread imaging (TSI) that can identify the spatiotemporal pattern of epileptic activity using Magnetoencephalography (MEG)., Methods: A three-dimensional grid of voxels covering the brain is created. The array-gain minimum-variance spatial filter is applied to an interictal spike to estimate the magnitude of the source and the time (Ta) when the magnitude exceeds a predefined threshold at each voxel. This calculation is performed through all spikes. Each voxel has the mean Ta () and spike number (N sp ), which is the number of spikes whose source exceeds the threshold. Then, a random resampling method is used to determine the cutoff value of N sp for the statistically reproducible pattern of the activity. Finally, all the voxels where the source exceeds the threshold reproducibly shown on the MRI with a color scale representing ., Results: Four patients with intractable mesial temporal lobe epilepsy (MTLE) were analyzed. In three patients, the common pattern of the overlap between the propagation and the hypometabolism shown by fluorodeoxyglucose-positron emission tomography (FDG-PET) was identified., Conclusions: TSI can visualize statistically reproducible patterns of the temporal and spatial spread of epileptic activity., Significance: TSI can assess the statistical significance of the spatiotemporal pattern based on its reproducibility., (Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

We investigated the effect of load against self-paced movement on cortical involvement for motor execution. Ten right-handed healthy volunteers were requested to perform brisk extension of the right index finger at self-paced intervals exceeding 10s for three load conditions: 0g, 50g and 100g. Movement-related magnetic fields were recorded using an MEG system. The signals were band-pass-filtered through 18-23Hz and rectified before averaging with respect to EMG onset. We analyzed the time course and %change of peak amplitude with reference to the baseline amplitude in event-related desynchronization (ERD) or synchronization (ERS) in each hemisphere. Maximum response was observed around the left somatomotor area for all conditions. ERD did not show any significant difference before the movement onset among the three load conditions. For %change, ERS in the post-movement period was significantly larger for the 100g load condition than for the 0g load condition, and that was significantly greater over the left than over the right hemisphere. These findings indicate that the load has little effect on pre-movement desynchronization, whereas it affects the post-movement synchronization on background rhythms., (Copyright © 2016 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.)

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., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Although dopamine plays an important role for motor control and modulates the frontal function via basal ganglia-thalamo-cortical loop, it is not known whether dopamine can affect the awareness of motor intention or not. To test this hypothesis, we applied Libet's clock paradigm to Parkinson's disease (PD) patients. Thirteen PD patients and 13 age-matched, healthy controls took part in the experiment which consisted of three judgment paradigms: W, M and S judgment. In W and M judgments, subjects were asked to press the key at self-willed timing. In W judgment, subjects reported the location of the clock's hand when they became aware of the intention (W-time). In M judgment, subjects reported the time when they became aware of the actual movement (M-time). In S judgment, subjects reported the time of the electrical stimulation given to their hand (S-time). W-time was significantly shorter in PD patients than in healthy control subjects while M-time and S-time were not different between the two groups. Delayed awareness of motor intention but not of action in PD patients might be related to dopamine depletion in those patients., (Copyright © 2015 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.)

Objective: The symptoms with optic ataxia suggest that simple and visually guided hand movements are controlled by 2 different neural substrates. To assess the differential frequency-coded posterior parietal cortex (PPC) role in planning visuo-motor goal-directed tasks, we studied the action specificity of event-related desynchronization (ERD) in this area., Methods: We investigated cortical activity by electroencephalography, while 16 healthy subjects performed self-paced reaching or wrist extension (control) movements. Time-frequency representations were calculated for each movement during the preparatory period., Results: ERD dynamics in upper alpha-band indicated that preparing a goal-directed action activates contralateral PPC to the moving hand around 1.2s before starting the movement, while this activation is later (around 0.7s) in preparing a not-goal-directed action. The posterior dominant rhythm had peak frequency of lower alpha-band at bilateral parietal., Conclusions: Posterior parietal cortex encodes goal-directed movement preparation through upper alpha-band activity, whereas general attention is processed via lower alpha-band oscillations., Significance: Preparing to reach an object engages posterior parietal cortex earlier than a not-goal directed movement., (Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: The pathophysiological mechanisms of partial reading epilepsy are still unclear. We delineated the spatial-temporal characteristics of reading-induced epileptic spikes and hemodynamic activation in a patient with partial reading epilepsy., Methods: Magnetoencephalography (MEG) was recorded during silent letter-by-letter reading, and the source of reading-induced spikes was estimated using equivalent current dipole (ECD) analysis. Diffusion tractography was employed to determine if the white matter pathway connected spike initiation and termination sites. Functional magnetic resonance imaging (fMRI) was employed to determine the spatial pattern of hemodynamic activation elicited by reading., Results: In 91 spike events, ECDs were clustered in the left posterior basal temporal area (pBTA) during Katakana reading. In 8 of these 91 events, when the patient continued to read >30 min, another ECD cluster appeared in the left ventral precentral gyrus/frontal operculum with a time-difference of ∼24 ms. Probabilistic diffusion tractography revealed that the long segment of the arcuate fasciculus connected these two regions. fMRI conjunction analysis indicated that both Katakana and Kanji reading activated the left pBTA, but Katakana activated the left lateral frontal areas more extensively than Kanji., Conclusions: Prolonged reading of Katakana induced hyper-activation of the cortical network involved in normal language function, concurrently serving as the seizure onset and symptomatogenic zones., Significance: Reflex epilepsy is believed to result from intrinsic hyper-excitability in the cortical regions recruited during behavioral states that trigger seizures. Our case shows that reading epilepsy can arise from a hyperexcitable network of cortical regions. Physiological activation of this network can have cumulative effects, resulting in greater reciprocal network propagation and electroclinical seizures. These effects, in turn, may give insights into the brain networks recruited by reading., (Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: We assessed the temporal-spatial characteristics of ictal direct current (DC) shifts (or infraslow activity) and high frequency oscillations (HFOs) in 16 patients with intractable focal epilepsy., Methods: The underlying etiology consisted of cortical dysplasia, glioma, hippocampal sclerosis, and low-grade neuroepithelial tumor in nine, four, two, and one patients, respectively. The median number of analyzed seizure events was 8.0 per patient (range: 2-10). Chronic electrocorticographic recording was performed with (1) a band-pass filter of 0.016-600Hz (or 0.016-300Hz) and a sampling rate of 2000Hz (or 1000Hz)., Results: Ictal DC shifts and a sustained form of ictal HFOs were observed in 75.0% and 50.0% of the patients, and 71.3% and 46.3% of the analyzed seizures. Visual assessment revealed that the onset of ictal DC shifts preceded that of ictal HFOs with statistical significance in 5/7 patients. The spatial extent of ictal DC shifts or HFOs was smaller than that of the conventionally defined seizure onset zone in 9/12 patients., Conclusion: Both ictal DC shifts and HFOs might represent the core of tissue generating seizures., Significance: The early occurrence of ictal DC shifts warrants further studies to determine the role of glia (possibly mediating ictal DC shifts) in seizure generation., (Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Purpose: To delineate chronological changes of cortical hyperexcitability by long-term follow-up of the amplitudes of somatosensory evoked potentials (SEPs) in patients with Japanese Unverricht-Lundborg disease (ULD)., Method: SEPs to median nerve stimulation were repeatedly examined in 7 genetically diagnosed ULD patients with the mean interval of 11.9 years. The degree of temporal changes in the amplitude of 3 early cortical components, N20, P25 and N35, to the age was analyzed and compared with that of healthy subjects., Results: Their clinical course was almost stable during the follow-up period, namely cessation of generalized tonic-clonic seizures and little or no progression of myoclonus. SEP amplitudes of P25 and N35 were enlarged in all patients and were gradually decreased with aging in ULD on average. The degree of temporal changes of P25 and N35 in ULD was similar or even lower than that of healthy subjects., Conclusion: Enlarged but relatively stable SEP amplitudes had a consistency with so-called self-limited clinical course in Japanese ULD. SEP amplitude could be one of the surrogate markers of the degree of cortical hyperexcitability in ULD during the long-term follow-up period., (Copyright © 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Objective: To evaluate lip sensory dysfunction in patients with inferior alveolar nerve injury by lip-stimulated somatosensory evoked fields (SEFs)., Methods: SEFs were recorded following electrical lip stimulation in 6 patients with unilateral lip sensory disturbance and 10 healthy volunteers. Lip stimulation was applied non-invasively to each side of the lip with the same intensity using pin electrodes., Results: All healthy volunteers showed the earliest response clearly and consistently at around 25ms (P25m) and at least one of the following components, P45m, P60m, or P80m, over the contralateral hemisphere. The ranges of the peak latencies were 23-33, 42-50, 56-67, and 72-98ms for right-side stimulation and 23-34, 46-49, 52-68, and 71-90ms for left-side stimulation. Affected-side stimulation did not evoke P25m component in any patients, but invoked traceable responses in 5 patients whose latencies were 57, 89, 65, 53, and 54ms. Unaffected-side stimulation induced P25m in 2 patients at 27 and 25ms, but not in the other 4 patients., Conclusion: The P25m component of lip SEFs can be an effective parameter to indicate lip sensory abnormality., Significance: Lip sensory dysfunction can be objectively evaluated using magnetoencephalography., (Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: Decreased early Bereitschaftspotential (BP) is one of the electrophysiological characteristics in patients with Parkinson's disease (PD). We examined whether PD patients could increase BP amplitude by means of neuro-feedback (NFB) training for their slow cortical potentials (SCPs)., Methods: We worked with 10 PD patients and 11 age-matched controls. BP was measured for self-paced button pressing by their right thumb. The subjects were instructed to make the introspective efforts to produce negative SCPs (negativation). The one-day session consisted of three trials, that is, the first BP, NFB training and the second BP, and each patient performed this routine for 2-4 days. Amplitudes of the first and second BPs were compared between the two groups that were divided depending on NFB performance., Results: Good NFB performance had the tendency of larger early BP in the second BP recording than in the first one, whereas in the poor NFB performance the early BP was smaller in the second BP recording than in the first one in both patient and normal groups (p < 0.001)., Conclusions: Good NFB performance of negativation could increase excitatory field potentials of pyramidal cells for the generation of early BP., Significance: Voluntary regulation of SCPs could enhance BP in PD patients and in aged controls., (Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: Auditory distance judgment relies on several acoustic cues and can be modulated by visual information. Sound intensity serves as one such cue as it decreases with increasing distance. In this magnetoencephalography (MEG) experiment, we tested whether N1m MEG responses, previously described to scale with sound intensity, are modulated by visual distance cues., Methods: We recorded behavioral and MEG data from 15 healthy normal hearing participants. Noise bursts at different sound pressure levels were paired with synchronous visual cues at different distances. We hypothesized that noise paired with far visual cues will be represented louder and result in increased N1m amplitudes compared to a pairing with close visual cues. This might be based on a compensation of visually induced distance when processing loudness., Results: Psychophysically, we observed no significant modulation of loudness judgments by visual cues. However, N1m MEG responses at about 100ms after stimulus onset were significantly stronger with distal compared to proximal visual cues in the left auditory cortex., Conclusions: Our results suggest an audio-visual interaction at an early stage in the left auditory cortex, possibly related to cue integration for auditory distance processing., Significance: Sound distance processing could prove itself as a promising model system for the investigation of intra-modal and cross-modal integration principles., (Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: Unilateral asterixis has been reported in patients with thalamic lesion. This study aims at elucidating the pathophysiology of the thalamic asterixis., Methods: Two cases with unilateral asterixis caused by an infarction in the lateral thalamus were studied by analysing the asterixis-related cortical activities, transcranial magnetic stimulation (TMS) for motor cortex excitability and probabilistic diffusion tractography for the thalamo-cortical connectivity., Results: Averaging of electroencephalogram (EEG) time-locked to the asterixis revealed rhythmic oscillations of a beta band at the central area contralateral to the affected hand. TMS revealed a decrease in the motor evoked potential (MEP) amplitude and a prolongation of the silent period (SP). The anatomical mapping of connections between the thalamus and cortical areas using a diffusion-weighted image (DWI) showed that the lateral thalamus involved by the infarction was connected to the premotor cortex, the primary motor cortex (M1) and the primary somatosensory cortex (S1) of the corresponding hemisphere., Conclusions: The thalamic asterixis is mediated by the sensorimotor cortex, which is subjected to excessive inhibition as a result of the thalamic lesion involving the ventral lateral nucleus., Significance: This is the first demonstration of participation of the sensorimotor cortex in the generation of asterixis due to the lateral thalamic lesion., (Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Quantitative measurement is required in clinical situation for sensory disturbance of the tongue due to lingual nerve injury. To assess disabled sensory function of the tongue, somatosensory evoked magnetic fields (SEFs) were measured following electric tongue stimulation in 13 patients with sensory disturbance by unilateral lingual nerve injury and in 10 age-matched healthy volunteers. Affected- and healthy-sides of the tongue were stimulated separately with the same intensity. Although the healthy-side stimulation induced clear responses over the contralateral hemisphere of all participants, the affected-side stimulation evoked hardly traceable responses in 6 patients and no activity in the remaining 7 patients. We evaluated the cortical activity via activated root-mean-square (aRMS), which is the time-averaged activity between 10 and 150 ms from the 18-channel RMS over the contralateral hemisphere. The laterality index of aRMS, expressed as [(left-right)/(left+right)], was out of the pre-defined normal range (-0.287 to 0.337) in 12 patients, and within the range in all healthy volunteers. The test sensitivity and specificity of the procedure were 92.3% and 100%, respectively. Tongue SEFs are reproducible and objective method to evaluate sensory disturbance of the tongue., (Copyright © 2011 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.)

Objective: To delineate long-term change of cortical excitability by measuring somatosensory evoked potentials (SEPs) in patients with Unverricht-Lundborg disease (ULD)., Methods: SEPs to median nerve stimulation were repeatedly examined in two genetically proven ULD patients manifesting stable condition over 16 years, namely disabling but non-progressive myoclonus and cessation of generalised tonic-clonic seizures., Results: In both patients, five sets of early cortical components were identified 16 years ago: two tangential components of N20-P20 and P30-N30 and three radial components of P25, N35 and N40. Cortical SEPs were regarded as abnormally enhanced 'giant' based on the N35 amplitude (>mean+3 SD of normal controls). The bimodal negative peaks of N35 and N40 showed different spatial distribution: N35 maximum in the central area and N40 in the centro-parietal area. At present, N35 remained giant while N40 disappeared in both patients., Conclusions: It is possible that currently preserved giant SEPs at least at N35 reflect disabling cortical myoclonus and that disappearance of N40 might reflect a lesser degree of increased cortico-cortical connectivity and/or decreased cortical hyperexcitability in the association cortices. It might possibly have resulted in the disappearance of GTCSs., Significance: We delineated long-term change of giant SEP in ULD., (Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: With advanced electroencephalography (EEG) technology, 'wideband EEG' ranging from slow shift to high frequency oscillation (HFO) is clinically available to study human epileptogenesis. The purpose of our study is to clarify the relationship between slow shift, HFO and conventional electrocorticographic (ECoG) change., Methods: A patient with right temporal lobe epilepsy who underwent presurgical evaluation with subdural electrodes was studied. Slow shift and HFO were evaluated in 16 habitual seizures with wideband EEG technique (bandpass filter of 0.016-600 Hz)., Results: Upon seizure occurrence in wideband ECoG, negative slow shifts coexisted with HFO (100-300 Hz) in the ictal onset zone in all investigated seizures. The former always preceded HFO and conventional initial EEG changes by mean value of 1.6 and 20.4s, respectively. The slow shifts and HFOs were observed only in the restricted ictal onset zone., Conclusions: In this particular patient, wideband EEG could delineate both ictal slow shift and HFO to define ictal onset zone, and the earliest occurrence of slow shifts may suggest an early role of glia in slow EEG shift generation than neurons., Significance: The time difference of the onset between ictal HFO and slow shift may help to understand epileptogenesis., (Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: Lateralization of functionally abnormal cortical area in autosomal dominant lateral temporal lobe epilepsy (ADLTE)., Methods: A sound pulse of pure tone was delivered monaurally to the ears alternately. Auditory evoked magnetic fields (AEF) were measured by using whole-head magnetoencephalography (MEG) system., Results: Significantly large N100m signals (a magnetic counterpart of N1/N100 in EEG) were detected in three out of five patients, either in the left or in the right hemisphere, contralateral to the auditory stimulation. The peak latency, location and orientation of distinct N100m exhibited no clear difference from those of normal controls., Conclusions: Unilateral cortical abnormality exists in some of the patients in ADLTE. Patients with abnormally large N100m had seizures apparently provoked by auditory stimuli, suggesting that the appearance of significantly large N100m is associated with the epileptogenicity. Based on the detailed examination using MRI and FDG-PET for two of the patients, the authors hypothesize hyperexcitability caused by the decreased inhibitory functions, larger number of synchronously activated neurons, or the elongation of neuronal firing in the pathological temporal cortex in ADLTE., Significance: The present study revealed clear abnormalities in the auditory cortex that have not been well detected by conventional EEG in patients with ADLTE.

Using magnetoencephalography, we measured 20-Hz activity induced after the common peroneal nerve (CPN) stimulation in 15 healthy subjects during the execution of foot movement or its motor imagery, and examined whether the 20-Hz activity is suppressed during motor imagery of foot movement. The prominent 20-Hz activity was contralaterally induced in the paracentral area after CPN stimulation, and it was almost completely suppressed during execution of the foot movement and partially suppressed during its motor imagery. These results suggest that the modulation of the 20-Hz activity is a useful indicator of the motor imagery of foot movement.

We previously reported that low-frequency electric cortical stimulation (LFECS) directly applied to the epileptic focus by means of subdural electrodes decreased the number of interictal epileptiform discharges in patients with intractable partial epilepsy. In the present study, LFECS was applied to the epileptic foci directly in four patients with medically intractable partial epilepsy through subdural electrodes and evaluated its effect on the number of interictal epileptiform discharges as well as simple partial seizures. We used alternating electric current of 0.3 ms duration presented at 0.9 Hz frequency for 250 s. LFECS did not induce seizures in any of the four patients. In one patient, the number of interictal epileptiform discharge decreased significantly by LFECS, which is in conformity with our previous report. In addition, LFECS applied to the seizure onset zone decreased the frequency of simple partial seizures in one patient. These results suggest that LFECS has an inhibitory effect not only on the interictal but also the ictal activities in patients with intractable partial epilepsy. Further study is required to determine the inhibitory effect of LFECS more in details.

Objective: To evaluate the suppressive effect of electric cortical stimulation upon the seizure onset zone and the non-epileptic cortex covered by subdural electrodes in patients with neocortical epilepsy and mesial temporal lobe epilepsy (MTLE)., Methods: Four patients with medically intractable focal epilepsy had implanted subdural electrodes for preoperative evaluation. Cortical functional mapping was performed by intermittently repeating bursts of electric stimulation, which consisted of 50 Hz alternating square pulse of 0.3 ms duration, 1-15 mA, within 5 s. The effect of this stimulation on the seizure onset zones and on the non-epileptic areas was evaluated by comparing spike frequency and electrocorticogram (ECoG) power spectra before and after stimulation. A similar comparison was performed in stimulation of 0.9 Hz of the seizure onset zones for 15 min., Results: When the seizure onset zone was stimulated with high frequency, spike frequency decreased by 24.7%. Logarithmic ECoG power spectra recorded at stimulated electrode significantly decreased in 10-32 Hz band by high frequency stimulation of the seizure onset zone, and in 14-32 Hz band by high frequency stimulation of the non-epileptic area. Low frequency stimulation of the seizure onset zone produced 18.5% spike reduction and slight power decrease in 12-14 Hz., Conclusions: Both high and low frequency electric cortical stimulation of the seizure onset zone have a suppressive effect on epileptogenicity. Reduction of ECoG fast activities after electric cortical stimulation suggests the augmentation of inhibitory mechanisms in human cortex.

Objective: To locate the visual motion complex (MT+) and study its response properties in an epilepsy surgery patient., Methods: A 17-year-old epilepsy patient underwent invasive monitoring with subdural electrodes in the right temporo-parieto-occipital area. MT+ was investigated by cortical electric stimulation and by epicortical visual evoked potentials time-locked to motion onset of sinusoidal gratings (motion VEP). Motion-related visual evoked magnetic field (motion VEF) was also recorded before the electrode implantation to complement the invasive recording., Results: Motion VEPs revealed two subregions within MT+, generating early and late potentials respectively. The early activity with a peak around 130 ms was localized at a single electrode situated immediately caudal to the initial portion of the ascending limb of the superior temporal sulcus (AL-STS). The late activity, peaking at 242-274 ms, was located ventro-rostrally over three electrodes. Among the four electrodes with motion VEPs, cortical stimulation at the most caudal pair elicited motion-in-depth perception involving the whole visual field. In addition to two subregions revealed on the gyral crown, magnetoencephalography (MEG) demonstrated another subregion with a late motion VEF in AL-STS immediately rostral to the electrode with the early motion VEP., Conclusions: In combination with MEG recording, the present invasive exploration demonstrated human MT+ in a focal area of the temporo-parieto-occipital junction and delineated possible three subregions as indicated by the different latencies and distributions of the motion VEP/VEFs., Significance: Comparative MEG and direct electrocorticographic recordings delineated possible subregions within the human MT complex.

Objective: Previous lesion studies in patients and functional imaging studies in normal subjects have led to the notion that the temporo-parietal junction (TPJ) has an integrative function for multisensory inputs. However, its electrophysiological properties such as response latencies and distributions of responses to various stimulus modalities in humans have not been fully investigated. The aim of the study is to clarify this issue., Methods: We recorded evoked potentials to different kinds of sensory stimuli including somatosensory, auditory and visual modalities in 6 patients with intractable partial epilepsy, who underwent chronic implantation of subdural electrodes in TPJ for presurgical evaluation., Results: In 5 out of 6 subjects, at least one electrode located in TPJ for each subject showed a maximum somatosensory evoked response commonly to electric, passive joint motion and pain stimuli. These electrodes showed the maximum responses also to tone stimuli in all of 4 subjects studied, and to visual motion stimuli in 3 out of 5 subjects studied. The polarity was consistent regardless of the stimulus modality within each individual subject, although the anatomical location, polarity and latency varied among subjects., Conclusions: A small area in TPJ for each individual subject receives sensory information of multiple modalities possibly coming from different receptive sites, although the electrophysiological properties of the responses may vary among subjects., Significance: We confirmed the convergence of somatosensory, auditory and visual evoked responses at human TPJ.