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Background DYT-TOR1A is caused by a GAG deletion in the TOR1A gene. While it usually manifests as early-onset dystonia, its phenotype is extremely diverse, even within one family. Recent reports have revealed that some DYT-TOR1A cases have novel mutations in the TOR1A gene while others have mutations in both TOR1A and another DYT gene (THAP1 or SGCE). Our understanding of the correlation between genotype and phenotype is becoming increasingly complicated. Case presentations: Here, we report on monozygotic twins who developed dystonia in childhood. The two children had different presentations in terms of onset age and dominant disturbances, but both exhibited marked diurnal fluctuation and jerking movements of the limbs as well as levodopa/levodopa-carbidopa responsiveness. These features are commonly associated with DYT/PARK-GCH1 and DYT-SGCE, yet these twins had no mutations in the GCH1 or SGCE genes. Whole exome sequencing eventually revealed a single GAG deletion in the TOR1A gene. Conclusion Monozygotic twins whose only mutation was a GAG deletion in TOR1A exhibited DYT/PARK-GCH1-asssociated features and jerking movements reminiscent of myoclonus. This finding may expand the spectrum of phenotypes associated with DYT-TOR1A, and suggests that levodopa has potential as a treatment for DYT-TOR1A with DYT/PARK-GCH1-associated features.

Objective To investigate the effect of guidelines for management of febrile seizures on the clinical practice, we conducted a nationwide survey in Japan. Methods The Japanese guidelines for management of febrile seizures 2015 (GL2015) was released in 2015. In 2016, a questionnaire was sent to all 512 certified hospitals (3 pediatricians each) of the Japan Pediatric Society and all 47 prefecture Pediatric Associations (10 private pediatricians each) in Japan asking about management policies for febrile seizures (FSs) during 2013–2014 and 2016. The questionnaires were about the following procedures: (1) lumbar punctures, blood examinations, and diazepam suppositories for children after a first simple FS at emergency departments; and (2) prophylactic diazepam during febrile illnesses in children with two or three past simple FSs, with no known predictors of recurrence. Results A total of 1327 pediatricians (66.2%) answered the questionnaire. Numbers of pediatricians performing lumbar punctures and blood examinations, and giving diazepam suppositories after a first simple FS were less in 2016 than in 2013–2014 (1.2% and 2.0%, 53.1% and 61.3%, and 36.7% and 51.9%, respectively). Pediatricians recommending prophylactic diazepam for children with two and three FSs decreased from 45.7% and 82.4% in 2013–2014 to 31.0% and 65.0% in 2016, respectively. Conclusion GL2015 had an effect on the clinical practices of pediatricians. On the other hand, 65% recommended prophylactic diazepam to children with three simple FSs even though GL2015 did not recommend use of diazepam based on number of previous FS. Anxiety about frequent seizures may affect pediatricians′ clinical practice.

Dihydropyrimidinase deficiency is a rare autosomal recessive disease affecting the second step of pyrimidine degradation. It is caused by mutations in the DPYS gene. Only approximately 30 cases have been reported to date, with a phenotypical variability ranging from asymptomatic to severe neurological illness. We report a case of dihydropyrimidinase deficiency incidentally detected by urine metabolome analysis. Gas chromatography-mass spectrometry-based urine metabolomics demonstrated significant elevations of dihydrouracil and dihydrothymine, which were subsequently confirmed by a quantitative analysis using liquid chromatography-tandem mass spectrometry. Genetic testing of the DPYS gene revealed two mutations: a novel mutation (c.175G > T) and a previously reported mutation (c.1469G > A). Dihydropyrimidinase deficiency is probably underdiagnosed, considering its wide phenotypical variability, nonspecific neurological presentations, and an estimated prevalence of 2/20,000. As severe 5-fluorouracil-associated toxicity has been reported in patients and carriers of congenital pyrimidine metabolic disorders, urinary pyrimidine analysis should be considered for those who will undergo 5-fluorouracil treatment.

Background Epilepsy and autism spectrum disorder (ASD) are the common neurological manifestations of tuberous sclerosis complex (TSC). EXIST-3 study has recently demonstrated that everolimus reduces seizures in patients with TSC and refractory epilepsy. Here we report the efficacy and safety of everolimus for treatment-refractory seizures in Japanese patients of EXIST-3, along with the exploratory analysis evaluating the everolimus effect on comorbid ASD symptoms in these patients. Methods Primary end point was change in seizure frequency from baseline defined as response rate (≥50% reduction) and median percentage reduction in the seizure frequency. Pervasive Developmental Disorders Autism Society Japan Rating Scale (PARS) scores were assessed at baseline and at week-18 for ASD symptoms. Results Overall, 35 Japanese patients were randomized to everolimus low-exposure (LE; n = 10), everolimus high-exposure (HE; n = 14), or placebo (n = 11). The response rate was 30.0% and 28.6% versus 0% with the everolimus LE and HE versus placebo arm, respectively. Similarly, the median percentage reduction in seizure frequency was 6.88% and 38.06% versus −6.67%. Stomatitis was the most frequently reported adverse event (everolimus LE, 100%; HE, 78.6%; placebo, 9.1%). Four of 11 patients with ASD in the everolimus arms and 1 of 8 patients with ASD in the placebo arm showed ≥5 point decrease in PARS scores. Conclusions Adjunctive everolimus treatment improved seizure frequency with a tolerable safety relative to placebo among 35 Japanese patients with TSC-associated refractory seizures, consistent with the results of overall EXIST-3 study involving 366 patients. A favorable trend towards the improvement of ASD symptoms was observed.

In 2015, the Japanese Society of Child Neurology released new guidelines for the management of febrile seizures, the first update of such guidelines since 1996. In 1988, the Conference on Febrile Convulsions in Japan published "Guidelines for the Treatment of Febrile Seizures." The Task Committee of the Conference proposed a revised version of the guidelines in 1996; that version released in 1996 was used for the next 19years in Japan for the clinical management of children with febrile seizures. Although the guidelines were very helpful for many clinicians, new guidelines were needed to reflect changes in public health and the dissemination of new medical evidence. The Japanese Society of Child Neurology formed a working group in 2012, and published the new guidelines in March 2015. The guidelines include emergency care, application of electroencephalography, neuroimaging, prophylactic diazepam, antipyretics, drugs needing special attention, and vaccines. While the new guidelines contain updated clinical recommendations, many unsolved questions remain. These questions should be clarified by future clinical research.

Objective To describe an assay of 5-methyltetrahydrofolate (5MTHF) in the cerebrospinal fluid (CSF) of children, to determine reference values, and to report the clinical significance of this assay in metabolic disorders affecting folate transport and metabolism. Methods CSF 5MTHF was determined by high-performance liquid chromatography with fluorescent detection in pediatric patients including one with FOLR1 gene mutation and one with methylenetetrahydrofolate reductase (MTHFR) deficiency. CSF total folate was measured using an automated analyzer. Results 5MTHF and total folate were determined in 188 and 93 CSF samples, respectively. CSF 5MTHF was high throughout the first six months of life and subsequently declined with age. Reference values of CSF 5MTHF and total folate were determined from 162 and 82 samples, respectively. The patient with FOLR1 gene mutation had extremely low CSF 5MTHF and total folate, though these values normalized after folinic acid supplementation. The patient with MTHFR deficiency had extremely low 5MTHF and moderately low total folate; these values were not associated and showed no significant change after folic acid supplementation. Conclusions This 5MTHF assay is simple, rapid, sensitive, reliable, and cost-effective. It will aid in the diagnosis and therapeutic monitoring of metabolic disorders affecting folate transport and metabolism.

Purpose To evaluate the long-term safety and seizure outcome in Japanese patients with Lennox–Gastaut syndrome (LGS) receiving adjunctive rufinamide therapy. Subjects and methods We conducted an open-label extension study following a 12-week multicenter, randomized, double-blind, placebo-controlled study of adjunctive rufinamide therapy in Japanese patients with LGS. Fifty-four patients participated in the extension study. Seizure frequency was evaluated until 52 weeks after the start of the extension study. Adverse events (AEs) were evaluated throughout both studies. Key findings Of the 54 patients, 41 (75.9%) completed the extension study. The median duration of exposure to rufinamide was 818.0 days in all 54 patients, and 38 patients (70.4%) received rufinamide for 2 years or more. The median percent change in the frequency of tonic–atonic seizures relative to the frequency at the start of the double-blind study was −39.3% (12 weeks), −40.6% (24 weeks), −46.8% (32 weeks), −47.6% (40 weeks), and −36.1% (52 weeks). Reduction of total seizure frequency was also maintained until 52 weeks. Frequent treatment-related AEs were somnolence (20.4%), decreased appetite (16.7%), transient seizure aggravation including status epilepticus (13.0%), vomiting (11.1%), and constipation (11.1%). Adverse events were mild or moderate, except for transient seizure aggravation in three patients. Adverse events resulting in discontinuation of rufinamide were decreased appetite, drug eruption, and worsening of underlying autism. When clinically notable weight loss was defined as a decrease ≥7% relative to baseline, 22 patients (40.7%) experienced weight loss at least once during long-term observation, although weight loss was reported as an AE in only three patients. Significance This study demonstrated a long-term benefit of rufinamide as adjunctive therapy for Japanese patients with LGS. Exacerbation of seizures and decreased appetite/weight loss should be monitored carefully.

This post hoc analysis of six randomized, double-blind, Phase II and III studies evaluated efficacy and safety of adjunctive perampanel (2-12 mg/day) in adolescent patients (aged ≥12 to ≤17 years) with uncontrolled partial-onset seizures, with or without secondarily generalized (SG) seizures, or primary generalized tonic-clonic (PGTC) seizures.Adolescent patients from Studies 304 (NCT00699972), 305 (NCT00699582), 306 (NCT00700310), 335 (NCT01618695), 235 (NCT01161524), and 332 (NCT01393743) were included. Efficacy assessments (split by seizure type) included median percent change in seizure frequency per 28 days from baseline and seizure-freedom rates. Safety assessments (all seizure types combined) included monitoring of treatment-emergent adverse events (TEAEs).The Safety Analysis Set included 372 adolescent patients (placebo, n = 114; perampanel, n = 258); the Full Analysis Set included 346 patients with partial-onset seizures (placebo, n = 103; perampanel, n = 243), of whom 125 experienced SG seizures during baseline (placebo, n = 37; perampanel, n = 88), and 22 with PGTC seizures (placebo, n = 9; perampanel, n = 13). Compared with placebo, perampanel 8 and 12 mg/day conferred greater median percent reductions in seizure frequency per 28 days for partial-onset seizures (18.0% vs 35.9% and 53.8% [both P 0.01]) and SG seizures (24.4% vs 72.8% [P 0.001] and 57.8% [P 0.01]), and greater seizure-freedom rates (partial-onset: 7.8% vs 13.2% and 11.8% [not statistically significant]; SG: 8.1% vs 40.7% [P 0.001] and 41.7% [P 0.01]). For PGTC seizures, and compared with placebo, perampanel 8 mg/day was also associated with greater median percent reductions in seizure frequency per 28 days (29.8% vs 88.0%) and greater seizure-freedom rates (11.1% vs 23.1%). Treatment-emergent adverse events were reported in 76 (66.7%) placebo- and 192 (74.4%) perampanel-treated patients (most common: dizziness, somnolence, headache, and nasopharyngitis). Serious TEAEs occurred in 5 (4.4%) placebo- and 11 (4.3%) perampanel-treated patients.Adjunctive perampanel was efficacious and generally well tolerated in adolescent patients with partial-onset, SG, or PGTC seizures and represents a potentially beneficial treatment option for adolescents with uncontrolled epilepsy.

Objective: Acute electroencephalogram (EEG) findings are important for diagnosing emergency patients with suspected neurological disorders, but they can be difficult for untrained medical staff to interpret. In this research, we will develop an emergency EEG trend figure that we hypothesize will be more easily understood by untrained staff compared with the raw original traces. Methods: For each of several EEG patterns (wakefulness, sleep, seizure activity, and encephalopathy), trend figures incorporating information on both amplitude and frequency were built. The accuracy of untrained reviewers’ interpretation was compared with that of the raw EEG trace interpretation. Results: The rate of correct answers was significantly higher in response to the EEG trend figures than to the raw traces showing wakefulness, sleep, and encephalopathy, but there was no difference when seizure activity patterns were viewed. The rates of misjudging normal or abnormal findings were significantly lower with the trend figures in the wakefulness pattern; in the other patterns, misjudgments were equally low for the trend figures and the raw traces. Conclusion: EEG trend figures improved the accuracy with which untrained medical staff interpreted emergency EEGs. Emergency EEG figures that can be understood intuitively with minimal training might improve the accuracy of emergency EEG interpretation. However, additional studies are required to confirm these results because there may be many types of clinical EEGs that are difficult to interpret.

SummaryPurposeTo evaluate the efficacy, safety, and pharmacokinetics of rufinamide as an adjunctive therapy for patients with Lennox–Gastaut syndrome (LGS) in a randomized, double-blind, placebo-controlled trial.MethodsWe conducted a multicenter clinical trial with a 4-week baseline, a 2-week titration, a 10-week maintenance, and either a follow-up visit or entry into an open-label extension. Patients with LGS (4 to 30 years old) taking between one and three antiepileptic drugs were recruited. After the baseline period, patients were randomly assigned to rufinamide or placebo. The primary efficacy variable was the percent change in the tonic–atonic seizure frequency per 28 days.Key findingsOf the 59 patients, 29 were randomized to the rufinamide group and 30 to the placebo group. The frequency of epileptic seizures was significantly decreased in the rufinamide group than in the placebo group; the median percent change in frequency of tonic–atonic seizures was −24.2% and −3.3%, respectively, (p=0.003) and that of total seizures was −32.9% and −3.1%, respectively (p

Purpose: Ictal fear is an uncommon condition in which fear manifests as the main feature of epileptic seizures. The literature has suggested that ictal fear is generally associated with poor seizure outcomes. We wanted to clarify the variability in seizure outcome of children with ictal fear. Subjects and methods: We identified five pediatric patients with ictal fear who were followed up on at Okayama University Hospital between January 2003 and December 2012. We retrospectively reviewed their clinical records and EEG findings. Results: The onset age of epilepsy ranged from 8 months to 9 years and 10 months. The common ictal symptoms were sudden fright, clinging to someone nearby, and subsequent impairment of consciousness, which were often accompanied by complex visual hallucinations and psychosis-like complaints. Ictal fear, in four patients, was perceived as a nonepileptic disorder by their parents. Ictal electroencephalograms (EEG) of ictal fear were obtained in all patients. Three showed frontal onset, while the other two showed centrotemporal or occipital onsets. Two patients were seizure free at last follow-up, while seizures persisted in the other three. A patient with seizure onset during infancy had a favorable outcome, which was considered to be compatible with benign partial epilepsy with affective symptoms. Conclusion: Ictal fear is not always associated with a symptomatic cause or a poor seizure outcome. It is quite important to make a correct diagnosis of ictal fear as early as possible to optimize treatment.

Purpose: To clarify the clinical implications of the preceding positive spikes (PPSs) observed primarily in rolandic spikes, we analyzed PPSs in the rolandic and occipital spikes observed in the electroencephalograms (EEGs) of patients with two types of benign partial epilepsies (benign childhood epilepsy with centro-temporal spikes [BECT] and Panayiotopoulos syndrome [PS]) and febrile seizures (FS). Subjects and methods: We identified patients from our outpatient EEG database that were seen between 2006 and 2008 that had BECT, PS, and FS with rolandic or occipital spikes. We generated an averaged spike for each patient from the rolandic and occipital spikes that were detected using an automatic spike detection and clustering system. We compared the presence rate of the averaged spikes with the PPS among the three groups (BECT vs. PS vs. FS) using sequential mapping. Results: We identified 25 BECT, 18 PS, and 15 FS patients with rolandic spikes. Fifteen BECT and nine PS patients exhibited a PPS in their averaged rolandic spikes, whereas only four FS patients did. Three of these four FS patients later developed afebrile seizures, and one of them was diagnosed as having PS. We analyzed eight PS and six FS patients with occipital spikes. Five PS patients exhibited a PPS in their averaged occipital spikes, whereas only one FS patient did. This FS patient later developed prolonged autonomic febrile seizures. Conclusion: PPSs are observed not only in rolandic spikes associated with BECT that is related strictly to sylvian seizures, but also in rolandic and occipital spikes associated with PS. Although PPSs are rare in such spikes observed in FS, patients with FS and PPSs may have an increased risk of developing afebrile seizures or prolonged autonomic febrile seizures. Further studies are warranted to determine the diagnostic utility of PPSs as a marker of the future development of epilepsy when they are observed in FS patients.

Purpose Epileptic spasms (ES) beyond infancy are a highly refractory type of seizures that require the development of an effective treatment. We therefore studied the efficacy and safety of topiramate (TPM), which is a drug that is indicated to be effective for intractable childhood epilepsy, for ES. Methods Out of 58 children with ES, we enrolled 33 patients treated with TPM at ≤12years of age. The administration of TPM was limited to cases of epilepsies that were resistant to any other potent treatment. We retrospectively investigated the efficacy of TPM for seizures and changes in electroencephalogram (EEG) findings. Results The median age at the start of TPM treatment was 5years, 8months. All patients had ES and 28 also had tonic seizures. As for the efficacy of TPM for all seizures, five patients became seizure-free and two had a ≥50% reduction in seizures. Seizure aggravation was observed in six patients. Of 29 patients whose EEG findings were compared before and during TPM treatment, nine showed EEG improvement with reduced epileptic discharges. Adverse effects were observed in 13 patients and included somnolence, anorexia, and irritability. In general, TPM was well tolerated. Conclusions TPM can be effective at suppressing very intractable ES in a proportion of patients who do not respond to any other treatment. The efficacy of TPM may be predictable based on EEG changes observed early in the course of treatment. TPM is promising for the treatment of extremely intractable childhood epilepsy and it has largely tolerable adverse effects.

We report here on 8 infants who showed paroxysmal downwards gaze (PDG). The time of initial appearance of PDG ranged from one month to five months (mean: 2.7 months) of corrected age. Seven out of eight patients showed interictal spikes in EEG, so they were started on prophylactic therapy with antiepileptic drugs. In five of the eight patients, PDG ceased, either spontaneously or with antiepileptic drug treatment, by four to eight months of corrected age. Six out of eight patients showed localized spikes and peculiar abnormal fast activity (AFA) in the occipital area and five of these patients later developed West syndrome. These AFA were observed on EEGs recorded at the time of initial PDG appearance, before hypsarrhythmia was observed and before tonic spasms appeared. We were able to exclude the possibility that PDG was a subtle epileptic seizure by confirming the temporal discordance between individual episodes of PDG and AFA with video-EEG monitoring. Yet topographic data showed that AFA in these patients was characteristically located in the occipital area, with a distribution similar to that of the fast activity which accompanied the tonic spasms that later developed in these patients. As a risk factor for developing WS, we propose the clinical symptom of PDG with characteristic occipital AFA visible in the EEG, both of which represent damage to the occipital region including the optic radiation.

To elucidate the pathophysiology of epileptic spasms, unaveraged time-frequency spectra of spasm-associated EEG gamma rhythms were investigated in 15 patients with West syndrome or related disorders. Using these unaveraged spectra, we were able to investigate in detail various aspects of the structure of ictal gamma rhythms that could not be examined using averaged spectra. The characteristics of the ictal gamma peaks (peak frequency, power, duration, and the number of peaks in each brain-region for each spasm) were statistically evaluated with respect to their differences among the brain regions and over the time-course of the clusters. Our findings were as follows: (1) Gamma peaks were clearly detected in most spectra and generally had a similar pattern in each spasm, which repeated in clusters. (2) The mean frequency of gamma peaks was 69.2 ± 16.8 Hz, and the number of peaks in each brain region of each spasm was 1.83 ± 1.16. (3) The occipitoparietal gamma peaks had significantly greater power and longer duration than the frontocentral peaks. (4) The frequency of the gamma peaks was higher in the mid phase of clusters than in the ending, and it tended to have a positive correlation with its latency from the preceding beta peak. An analysis of the ictal gamma rhythms might give some insight into the generative mechanism of spasms.

To clarify the characteristics of the mode of appearance and morphology of epileptiform discharges before the onset of West syndrome (WS). The subjects were 25 infants whose electroencephalograms (EEGs) were recorded before the onset of WS and whose first EEG was recorded before 6 months of corrected age (CA). We extensively analyzed the chronological and topographical changes of the epileptiform discharges before the onset of WS. The location of the initial epileptiform discharges was in the posterior areas in 14 (Group O), the multiple areas in 7 (Group M), and areas other than occipital in 4 (Group non-O). Twelve of the 14 patients in Group O were premature infants, and all but one had PVL. Most patients in Group M were full-term infants or near full-term infants who had hypoxic damage. The ages at the appearance of the initial epileptiform discharges in Group O were significantly later than those in Group M: 3.0-5.9 months of CA in Group O vs. -0.1 to 2.0 months of CA in Group M. These facts suggest that the difference of brain damage is related to both the topographical characteristics and the age at the appearance of initial epileptiform discharges, and around 3 months of CA is a critical period for the appearance of occipital hyperexcitability. Hypsarrhythmia and tonic spasms appeared almost simultaneously from 4 to 6 months of CA in most patients. To predict the occurrence of WS in high-risk infants, EEG follow-ups from early infancy are very useful.

To clarify the diagnostic issues and treatment of patients with cryptogenic or symptomatic generalized epilepsies, not including West syndrome (WS), we investigated electroclinical change during the clinical course, and treatment effects in these patients. The selection criteria were minor generalized seizures as their main seizure type and diffuse epileptic discharges as their main EEG findings. Regarding EEG, we included EEGs that predominantly displayed multifocal spike-waves because of the inclusion of severe epilepsy with multiple independent spike foci (SE-MISF). We divided the subjects into two groups according to their main seizure types: Group A (54 patients) with brief tonic seizures and Group B (24 patients) with myoclonic seizures and/or atypical absences. The main epileptic syndromes were considered to be Lennox-Gastaut syndrome and SE-MISF in Group A, and epilepsy with myoclonic-astatic seizures in Group B. A history of WS was often seen in Group A, but it was exceptional in Group B. During the clinical course, seizure types did not basically change in Group A. EEG patterns were changeable in both groups. Although there was some overlap in electroclinical manifestations among epileptic syndromes, a transition between the two groups was not seen. High-dose valproate and ethosuximide were the most effective in Groups A and B, respectively. Long-term prognosis was significantly more favorable in Group B than in Group A.

Panayiotopoulos syndrome (PS) is a type of benign childhood partial epilepsy, which has a good prognosis despite the fact that it is frequently associated with abundant multifocal spikes on the electroencephalography (EEG). We investigated whether stable dipoles, as seen in rolandic epilepsy, were also present in PS. We performed dipole analysis of the interictal spike discharges seen in the interictal EEGs of eight children with PS. We chose more than 10 spikes for each kind of spike, and investigated whether or not more than three of these spikes showed consistently stable dipole locations. (1) We observed 15 different kinds of spikes in various regions in the EEGs of the eight children. (2) Twelve of the 15 kinds of spikes had dipoles with a high goodness of fit. Furthermore, 14 of the 15 spikes had stable dipoles with similar locations for more than three individual spikes. (3) Fourteen of the 15 spikes, including frontal spikes, showed dense dipole locations in the mesial occipital area. Thirteen of these 14 spikes also showed other dipole locations in the rolandic area and/or the vertex (Cz). Our study revealed that the various types of spikes observed in PS have similar and stable dipole locations. The dipoles showing high stability, were located in the mesial occipital area, and were accompanied by dipoles located in the rolandic area. The stability and location of these dipoles indicate that there may be a pathogenetic link between PS and rolandic epilepsy.

Objective : We tried to determine the error range of dipole modeling for EEG spikes originating from various clinically important sources by a simulation study employing a realistic head model. The computed error range was also compared with the degree of disturbance of dipole modeling caused by adding background activity to the spike. Methods : The scalp fields generated by temporal, frontal and rolandic epileptic sources with spatial extent were simulated, and the corresponding 3-dimensional maps of residual variance (RV) were built by computing the RV for a single dipole at each point on a fine imaginary grid in the brain. Single dipole modeling was also performed for the simulated scalp fields after adding real background activity. Results : The brain volume corresponding to a small RV was compact for the frontal sources and the lateral and baso-mesial temporal sources, and large for the anterior and baso-lateral temporal sources. The distribution of dipoles estimated for spikes contaminated with background corresponded to that of the volume of small RV and to spike-amplitude. Estimates were improved by employing inferior temporal electrodes. Conclusions : When evaluating dipole models of epileptic spikes, error ranges can be estimated and they vary considerably from region to region. Significance : This study illustrates the variability of the error in dipole modeling of epileptic spikes. This variability is important when considering the clinical interpretation of modeling results.

Objectives : We propose a combination of independent component analysis (ICA) and recursively applied and projected multiple signal classification (RAP-MUSIC) as a new approach to dipole source estimation of epileptiform discharges. The method is minimally dependent on subjective decisions. Methods : Ten electroencephalographic (EEG) data matrices were generated by computer, each matrix including real background activity from a normal subject and an array of added simulated spikes. Each spike was a summation of two transients originating from slightly different ‘original dipole sources'. The unaveraged EEG matrices were decomposed by ICA, and source estimation was performed by applying RAP-MUSIC to the spatial information defined by the ICA components showing epileptiform activity in their waveform. For comparison, dipoles were also estimated from the same matrices using two existing methods: RAP-MUSIC based on eigen-decomposition of the covariance matrices of averaged spikes and common spatial pattern decomposition. Results : In every simulated EEG data matrix, two dipoles close to the original sources were estimated by the present method. Their unaveraged activities were also similar to those of the original sources. The two existing methods gave less precise results than the proposed method. Conclusions : RAP-MUSIC based on ICA thus proved promising for source estimation of unaveraged epileptiform discharges.

We designed a combination of independent component analysis (ICA) and recursively applied and projected multiple signal classification (RAP-MUSIC) as a new approach to dipole source estimation of epileptiform discharges. The estimation is minimally influenced by subjective decisions in this analysis. A simulation study was performed by generating 10 EEG data matrices by means of a computer: each matrix included real background activity from a normal subject to which an array of simulated unaveraged spikes was added. Each discharge was a summation of two transients originating from slightly different “original dipole sources”. The simulated spikes in the unaveraged EEG data were extracted from the background by ICA as spatiotemporal components, each component having fixed potential field distribution and maximally independent waveform. The complete separation between spikes and background was objectively proven by reconstruction of the EEG from the decomposed components. RAP-MUSIC was performed based on the spatial information included in the epileptic ICA components. RAP-MUSIC does not involve subjective decisions such as selection of multiple local score peaks, determination of the number of dipoles or initial guesses of dipole parameters. In every simulated EEG data matrix, two dipoles close to the original sources were estimated. Their activities were also similar to those of the original sources. For comparison, the same simulated EEG data were averaged and subjected to RAP-MUSIC using eigen-decomposition of the covariance matrices. Only one dipole was estimated in every simulation by this conventional method and therefore the result of the present method was better. RAP-MUSIC based on ICA, thus, proved promising for source estimation of unaveraged epileptiform discharges.

Purpose: In this study, we tried to show that EEG and MEG are clinically complementary to each other and that a combination of both technologies is useful for the precise diagnosis of epileptic focus. Subjects and methods: We recorded EEGs and MEGs simultaneously and analyzed dipoles in five patients suffering from intractable localization-related epilepsy with ages ranging from 13 to 19 years. MEG dipoles were analyzed using a BTI Magnes 148-channel magnetometer. EEG dipoles were analyzed using a realistically shaped four-layered head model (scalp–skull–liquor–brain) built from 2.5-mm-slice MRI images. Results: (1) In two of five patients, MEG could not detect any epileptiform discharges, while EEG showed clear spikes. However, dipoles estimated from the MEG data correspond to the early phase of EEG spikes clustered at a location close to that of the EEG-detected dipole. (2) In two of five patients, EEG showed only intermittent high-voltage slow waves (HVSs) without definite spikes. However, MEG showed clear epileptiform discharges preceding these EEG-detected HVSs. Dipoles estimated for these EEG-detected HVSs were located at a location close to that of the MEG-detected dipoles. Conclusion: Simultaneous recording of MEG and EEG with dipole modeling is more useful for accurate determination of epileptic focus than either technique alone.

Objective : We report on a patient who showed an unusual transition from complex partial seizures to a combination of myoclonic seizures and partial seizures, and then to isolated myoclonic seizures. The pathophysiological mechanism of the myoclonic seizures in this uncommon condition was studied. Methods : The interhemispheric small time differences were estimated in the ictal EEG discharges of myoclonic seizures for differentiation between primary and secondary bilateral synchrony. The estimation was performed by coherence and phase analysis based on the two-dimensional autoregressive model. Results : The estimated interhemispheric time differences were at most 27.4 ms. The ictal activity of the myoclonic seizures was suggested to originate from a cortical focus in the right hemisphere, which was also the origin of the partial seizures. Conclusion : The patient was considered to have an unusual type of myoclonic seizures with a probable pathophysiological mechanism of secondary bilateral synchrony.

Objective: We developed a novel non-invasive analysis to localize the source and visualize the time course of electrical activity generated inside the brain but unclear from the scalp. This analysis applies to signals with unique waveform characteristics, such as seizures. Methods: The method extracts activity from an EEG data matrix as a spatiotemporal component having waveforms uncorrelated to the other concurrent activities. The method also provides the location and orientation of the dipole generating this activity. We applied this method to ten scalp seizures in three patients with temporal lobe epilepsy and single-focus seizures confirmed by intracerebral recordings. A realistic head model based on MRI was used for computation of field distributions. Results: When seizure activity was still not visually identifiable on the scalp, the method demonstrated in all scalp seizures a source in the temporal neocortex corresponding clearly to the region of seizure activity in intracerebral recordings. Frequency characteristics of the estimated activities also resembled those of the intracerebral seizures. Conclusions: This method enables estimation of focal brain activity when its effect on scalp EEG is unclear to visual examination. It works in situations where currently available source analyses methods, which require noiseless definite activity, are not applicable.

For precise identification of an epileptic focus in mesial temporal lobe epilepsy (MTLE), various techniques, including neuroimaging, are employed. We performed topographic and spike dipole analyses to investigate the correlation between surface electroencephalogram (EEG) and the location of the lesion in 10 patients with MTLE. Six patients with interictal epileptic spikes on EEG were analyzed by the dipole localization method using CDT 1000 (Central Electronics Company, Tokyo). The location of the spike dipoles were compared with the location of abnormal lesions revealed by magnetic resonance imaging (MRI). In all 10 cases, EEG topography was also performed to determine an abnormal lesion from the EEG background activity. In six cases, spike dipoles were located at the mesial temporal lobe, which corresponded to the MRI lesion. In seven of the 10 cases, EEG topography revealed the deviation of the delta band to one side in the frontal to anterior temporal area. In these seven cases, the laterality of the delta band deviation coincided with the site of the MRI abnormality. In one case, a topographic abnormality was provoked after sleep deprivation. We conclude that EEG analysis combined with MRI is useful for the evaluation of the epileptic focus in MTLE. Topographic analysis of basic EEG was considered to be beneficial especially in MTLE, in which epileptic spikes were rare.

A simple and rapid method for the quantitation of concentrations of lamotrigine, a novel antiepileptic, in human serum was developed with high-performance liquid chromatography, using a solid-phase extraction technique. The mobile phase was composed of acetonitrile-10 mM phosphate buffer (pH 3.5) containing 5 mM sodium octanesulphonate (27:73, v/v), and components were detected at 265 nm. Retention times of acetanilide as an internal standard and lamotrigine were 3.4 and 10.3 min, respectively. The coefficients of variation were 3.1-4.5% and 4.4-9.8% for the within-day and between-day precision estimates, respectively. The extraction recovery of lamotrigine added to blank serum was 86-107%. The quantitation limit of lamotrigine was ca. 0.2 microgram/ml in 100 microliters of serum. These results suggest that the method employed in this study is useful for the routine monitoring of serum concentrations of lamotrigine in epileptic patients.

We analyzed spike-associated high-frequency oscillations (HFOs) and their relationship to spike foci in electroencephalograms (EEGs) of patients with benign epilepsy with centrotemporal spikes (BECTS) and Panayiotopoulos syndrome (PS). In 35 patients with BECTS and 29 with PS, focal spikes in scalp sleep EEGs were firstly classified into clusterings according to their characteristics including shapes and distributions. In each patient, the maximum of three spike clusters were investigated through time–frequency and single-dipole analyses to explore relationships between presence or absence of spike-associated HFOs and the distribution of estimated spike sources. A total of 159 spike clusters was analyzed (96 in BECTS and 63 in PS). HFOs were detected in 73 spike clusters (76.0%) in BECTS and 37 (58.7%) in PS with a statistically significant difference ( p = 0.024 by Fisher’s exact test). In BECTS, the spike sources had a close relationship with HFOs and were largely uniform irrespective of presence or absence of HFOs. In contrast in PS, the spikes tended to be dispersed and the rate of association with HFOs was significantly higher in occipito-parietal spikes (29/39) than the others (8/24; p = 0.002) suggesting that occipito-parietal spikes with a close link to HFOs were indicated to have a particular meaning in the epileptogenesis.