[Aggravation of epilepsy by valproate sodium in a child with cryptogenic localization-related epilepsy]

We report a paradoxical effect of valproate sodium (VPA) observed in a 3-year-old girl with cryptogenic localization-related epilepsy. On admission she experienced two types of seizures that were confirmed by ictal EEGs : complex partial seizures (CPSs) originating from the left hemisphere and combined seizures that began with repetitive myoclonic seizures immediately followed by a CPS. These myoclonic seizures did not possess asymmetrical features, but the ictal EEGs showed left-side dominant multiple spike-waves. The patent's interictal EEGs on admission showed left posterior temporal- parietal spikes during wakefulness and frequent diffuse spike-waves during sleep. In the process of introduction and increase in the dosage of VPA, an aggravation of epileptic discharges, especially a dramatic increase in diffuse spike-waves during sleep, was observed. In the same period of time, myoclonic seizures not followed by CPS newly appeared, and there was an increase in the frequency of CPSs and combined seizures. Marked improvement of epileptic discharges, namely the disappearance of diffuse discharges, and complete suppression of all types of seizures were achieved by the introduction of carbamazepine (CBZ) along with the withdrawal of VPA. During the clinical course, the patient did not display any signs or symptoms of VPA encephalitis, overdose of VPA or metabolic aberration. The paradoxical effect of CBZ in localization-related epilepsy is well-known, yet in this case, VPA displayed a similar paradoxical effect. Additionally, CBZ was efficacious in the suppression of secondary bilateral synchrony on EEG and also successfully controlled CPSs, combined seizures and myoclonic seizures.

Scalp-recorded high-frequency oscillations in childhood sleep-induced electrical status epilepticus

Because high-frequency oscillations (HFOs) may affect normal brain functions, we examined them using electroencephalography (EEG) in epilepsy with continuous spike-waves during slow-wave sleep (CSWS), a condition that can cause neuropsychological regression. In 10 children between 6 and 9 years of age with epilepsy with CSWS or related disorders, we investigated HFOs in scalp EEG spikes during slow-wave sleep through temporal expansion of the EEG traces with a low-cut frequency filter at 70 Hz as well as through time-frequency power spectral analysis. HFOs (ripples) concurrent with spikes were detected in the temporally expanded traces, and the frequency of the high-frequency peak with the greatest power in each patient's spectra ranged from 97.7 to 140.6 Hz. This is the first report on the detection of HFOs from scalp EEG recordings in epileptic patients. We speculate that epileptic HFOs may interfere with higher brain functions in epilepsy with CSWS.

[Clinical application of the modified Stroop test to children with attention deficit/hyperactivity disorder]

The Stroop test has been already applied to many children with attention deficit/hyperactivity disorder (AD/HD). There are, however, differences in the measurement of the Stroop test, and also in the background conditions of the patients, such as the status of comorbidity with learning disorder (LD), medication and the level of Intelligence Quotient (IQ), and presumably as a result, the outcome of the Stroop test shows a diversity. This study was undertaken to compare the performances of children with AD/HD to normal controls using the modified Stroop test according to the subtypes of AD/HD. Subjects in this study were 23 unmedicated children with AD/HD, ranging from 6 to 14 years of age, and 69 normal controls who were matched on sex and age. Children with AD/HD whose verbal IQ and performance IQ were above 80 showed significant differences in such indices as Incongruent Color Naming time (ICN) and the resulting index of subtracting Color Naming time (CN) from ICN (ICN-CN). As to the analysis according to the subtypes excluding 8 cases with comorbid LD, both the predominantly inattentive type and the group putting together the predominantly hyperactive-impulsive type and the combined type showed significant differences in ICN--CN compared with the normal controls. These results suggest that the inattentiveness relevant factor affects the performance of the interference task in children with AD/HD.

Characteristics of the synchronous occipital and frontopolar spike phenomenon in Panayiotopoulos syndrome

PURPOSE

The synchronous appearance of an occipital and frontopolar spike (the Fp-O spike) is characteristic of Panayiotopoulos syndrome (PS). This phenomenon is also seen in various other types of epilepsy, particularly those that occur in childhood. Using dipole analysis and sequential mapping, we investigated the characteristics of the Fp-O spike observed in seven patients with PS and six patients with symptomatic localization-related epilepsy in childhood (SLE).

METHODS

We analyzed both one averaged spike and 20 manually selected successive individual Fp-O spikes for each patient through sequential topographical mapping with steps of 10 ms from 40 ms before to 40 ms after the negative maximum peak of each spike. For dipole analysis, a period of 40 ms before the maximum negative peak of the averaged spike in each patient was examined using equivalent current dipole localization software.

RESULTS

Sequential mapping revealed that occipital negative peaks preceded frontal negative peaks in all of the PS patients, as well as in two of the six SLE patients. The four remaining SLE patients did not exhibit preceding occipital peaks. In all of the patients with PS, representative dipole locations were in the posterior area, whereas in SLE patients they were scattered over more anterior areas. The estimated sources of the Fp-O and O spikes appeared to have the same position and orientation in the two PS patients.

CONCLUSION

We conclude that Fp-O spikes in PS occur as the result of a rapid spread of epileptic activity from the posterior areas to the anterior areas of the brain. Fp-O spikes in PS patients show a uniform topographical pattern and dipole location, whereas those in other patients show more heterogeneity in these features. These findings support the homogeneity of PS and thus its designation as a syndrome.

Electroclinical characterization and classification of symptomatic epilepsies with very early onset by multiple correspondence analysis

PURPOSE

To characterize very early onset symptomatic epilepsies electroclinically, to identify meaningful factors to delineate epilepsy syndromes under this category, and to test validity of the current syndromic organization of these epilepsies by the International League Against Epilepsy (ILAE).

METHODS

Subjects were 38 epileptic patients with seizure onset before 3 months of age. We investigated the age of seizure onset, seizure types, myoclonus, EEG features, neuroimaging studies, outcome of seizures and development. We performed multiple correspondence analysis (MCA) to reveal associations among these characteristics and to find important characteristics to divide this epilepsy group into subgroups.

RESULTS

Very early onset epilepsies were characterized by partial seizures and epileptic spasms, especially occurring in combination as a single ictal event (combined seizures), and poor outcome. Suppression-burst (SB), hypsarrhythmia, EEG asymmetry and structural brain abnormalities were common. MCA demonstrated that presence or absence of SB was the most meaningful factor to separate this group into subgroups. MCA on the subgroup with SB revealed a subset with early-onset spasms, partial seizures with single focus, no myoclonus, SB during wakefulness and sleep, no EEG asynchrony, hypsarrhythmia and combined seizures, and another subset with late-onset spasms, partial seizures with multiple foci, myoclonus, EEG asynchrony, no combined seizures, SB during sleep only, no EEG asymmetry, no structural abnormality and no hypsarrhythmia. These corresponded to Ohtahara syndrome and early myoclonic encephalopathy, respectively.

CONCLUSIONS

Very early onset symptomatic epilepsies have the electroclinical characteristics distinct from those with later onset. This study supported the current ILAE organization on this epilepsy group from statistic approach.

[Developmental changes in visuospatial working memory]

We investigated the developmental changes in visuospatial working memory using the Visuospatial Span Task (VST) and the Matrix Visuospatial Working Memory Test (VSWMT). VST is a short-term storage task, while VSWMT is a complex dual task. VSWMT requires the use of storage, processing, and selective attention, all of which are thought to be supported by the central executive (Baddeley). The subjects of this study were 60 typically developing children (43 boys and 17 girls) aged 6-14 years (average 10.4 years). For each task we evaluated span scores and the number of total passed trials, and investigated the changes that occurred with age. To further elucidate age-related changes in visuospatial working memory, we divided the subjects into three age groups (Group A: 6-8 years, Group B: 9-11 years, and Group C: 12-14 years of age), and statistically evaluated the differences between the groups. In both tasks, span scores and the number of total passed trials showed definite age-related changes from 6 to 14 years of age. Span scores and the number of total passed trials in VSMWT continued to increase until adolescence, with significant differences between the three age groups, while those in VST increased significantly between Groups A and B (the number of total passed trials only) and between Groups A and C (span scores and the number of total passed trials); there was no significant difference between Groups B and C, however. These results suggest that the network of the brain involved in visuospatial working memory gradually matures during early school years and adolescence, and that the basic mechanisms of this network exist by 6-7 years of age. Our results also show that VST and VSWMT are suitable tests for the evaluation of visuospatial working memory in childhood and adolescence.

[Treatment of adult patients with childhood-onset epilepsy by child neurologists]

A significant number of patients with childhood-onset epilepsy continue to be treated by child neurologists after reaching adulthood. In this article, the issue of these so-called carry-over cases is discussed based on the results of two studies: our previous study on carry-over patients at the Department of Child Neurology, Okayama University Hospital, and a questionnaire survey on carry-over cases by the Japan Epilepsy Society. These two studies revealed that child neurologists currently treat many carry-over epilepsy patients in Japan, and that these patients, even those who have low seizure frequencies or are in remission, suffer from many problems such as comorbidities and socioeconomic difficulties. To ameliorate these problems, a comprehensive care system should be established, based on cooperation between various kinds of doctors and comedical staff members.

Age-dependent spike localization in various epileptic syndromes

The electroencephalograms from 276 patients with localization-related epilepsy were analyzed to compare the distribution of spike foci in different age groups. Patients were divided into five groups according to spike location in the frontal, central, temporal, occipital, or multiple cortical regions. The age of peak incidence was earliest in patients with occipital foci, followed by those with central foci and then those with frontal foci. A bimodal age distribution of patients with temporal foci was observed. Symptomatic patients frequently exhibited multiple and frontal foci, and a large number of idiopathic patients had central, temporal, and occipital foci. Multiple foci were detected in 27.5% of idiopathic patients. Age-related spike localization was uniformly observed, regardless of the epileptic syndrome. The analysis of these data indicates that there are two types of multiple foci, one correlated with organic lesions and the other with an idiopathic, functional nature.

Detection of seizure-associated high-frequency oscillations above 500Hz

High-frequency oscillations (HFOs) of up to 500Hz in EEG are considered to have close relation with ictogenesis. We had the unique opportunity to record a seizure in EEG with intracerebral macroelectrodes and a sampling frequency of 10kHz. Considering the notion that faster HFOs are likely more ictogenic, we investigated this ictal EEG data to find if even faster HFOs were present. HFOs were investigated in interictal spikes and seizure activity using time-frequency spectra: t values corresponding to frequencies from 100 to 1000Hz were obtained by comparison to the background and controlled by the false discovery rate (FDR). The seizure had a right hippocampal onset. HFOs up to 800Hz as well as HFOs below 500Hz built up in the hippocampal discharges more at the beginning of the seizure and during the preictal period than in the interictal period. These HFOs were visually confirmed in temporally expanded EEG traces. We demonstrated for the first time the existence of HFOs above 500Hz and up to 800Hz with intracerebral macroelectrodes in an epileptic patient; they occurred primarily in association with the seizure discharge. HFOs above 500Hz possibly reflect facilitation of ictogenic neuronal hypersynchronization.

[Reappraisal of vitamin B6 therapy for West syndrome]

Vitamin B6 (VB6) is used frequently as one of the first-choice drug for the treatment of West syndrome (WS) in Japan. We report 2 cases of symptomatic WS who had a good response to readministration of VB6. Case 1 was a 3-year-old girl diagnosed as having severe hydroencephalus. She developed WS at the age of 9 months. She was treated with ACTH, but relapsed when she was 1 year old. Despite treatment with various conventional drugs and second ACTH therapy, her seizures were not suppressed. We reviewed past treatment records in another hospital, and found that VB, treatment was stopped because her EEG did not improve within a week. We then retried VB6 therapy when she was 3 years and 6 months old, and as a result she became seizure-free and hypsarrhythmia disappeared on EEG within a month. Case 2 was a boy with severe cerebral palsy who was diagnosed as having WS at the age of 9 months. His MRI revealed bilateral subdural hematoma. Treatment was started with VB6, and he became seizure-free within several days. But 7 days after starting VB6, treatment was stopped because of the side effects. VPA was started instead, but his EEG showed gradual worsening. Then, we added a smaller dose of VB6 to VPA. His EEG improved dramatically, and his seizures have been controlled without any side effects. The present cases indicate the possible clinical usefulness of successful VB6 retrials even in older patients with severe organic lesions, by means of combined therapy with other drug, and alternative design of the dosing. However, we suspect there might be many cases in which the efficacy of VB6 therapy has not been properly assessed due to the short observation period and/or side effects.

[Standard value and developmental changes in the indices of interference effect in the modified Stroop test]

The Stroop test was originally invented by Stroop to measure selective attention and cognitive flexibility and various versions of this test have been developed by many other researchers. Since the Stroop test requires the examinee's sustained efforts, it is not readily applicable to children with developmental disorders. In order to overcome this weakness, a modified Stroop test by reducing the total number of stimulations from 300 to 72 was proposed for clinical use. This study was performed to obtain the standard value of the modified Stroop test, and also to clarify the developmental changes in indices of interference effect. Two hundred eighty one normal children and adults, ranging from 6 to 20 years of age were examined. A simple regression analysis was performed to examine the relation between age and the score of indices such as Incongruent Color Naming (ICN), ICN--Color Naming (CN), ICN/CN. The results from this analysis showed significant age-related changes. Subjects between sixteen and seventeen showed the best score in each index. These findings suggest that a brain region and/or functional system of late maturation might participate in the execution of the interference task.

Mycophenolate mofetil therapy for childhood-onset steroid dependent nephrotic syndrome after long-term cyclosporine: extended experience in a single center

BACKGROUND

Mycophenolate mofetil (MMF) is being used increasingly in children with steroid-dependent nephrotic syndrome (SDNS). However, there is limited information on the optimal therapeutic range for mycophenolic acid (MPA), the active metabolite of MMF, in these patients.

METHODS

26 patients with SDNS (mean age 13.1 years, 19 with minimal change disease and 7 with focal segmental glomerulosclerosis) who had received MMF for at least 6 months after longterm cyclosporine (CsA, mean 56 months) at Saitama Children's Medical Center between September 2002 and August 2008 were analyzed. MMF was introduced at an initial dose of 250 mg/12 h, adjusted to maintain target predose MPA at greater than 2 microg/ml (maximum 1 g twice daily) gradually over 4 weeks. After the introduction of MMF, the dosages of both CsA and prednisolone (PSL) were tapered off if possible.

RESULTS

The mean MMF dose required was 34 +/- 6 mg/kg, which maintained the mean predose MPA levels of 3.1 mg/ml. In 26 patients, treatment with MMF for a mean follow-up period of 19 months (range 7 - 42), resulted in a reduction of the mean PSL dose from 0.33 +/- 0.23 to 0.17 +/- 0.11 mg/kg per day (p < 0.01) and mean CsA dose from 3.2 +/- 1.7 to 1.3 +/- 1.8 mg/kg per day (p < 0.01). The mean 12-monthly relapse rates decreased from 2.5 +/- 1.4 to 0.8 +/- 1.2 episodes (p < 0.01). In 20 patients treated with MMF (77%), the dose of PSL and/or CsA was successfully tapered with a reduction in the relapse rates. In 6 patients, however, CsA therapy was reintroduced or its dose was increased because of treatment failure. The patients whose average predose MPA levels were less than 3 microg/ml were significantly likely to have treatment failure (p < 0.05). 2 patients reduced the MMF dosage because of anemia or herpes labialis. However, no severe gastrointestinal discomfort was seen in any patients. Despite long-term CsA therapy, marked tubulointerstitial fibrosis developed during MMF therapy in surveillance biopsies of only one of these five patients.

CONCLUSIONS

Therapy with MMF based on the predose MPA levels can be a less toxic alternative to CsA or in some cases a useful additional medication to allow for a reduction in the CsA and/or PSL dosage.

Abnormal fast activity in infancy with paroxysmal downwards gaze

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.

Complex partial status epilepticus in children with epilepsy

PURPOSE

Complex partial status epilepticus (CPSE) is often under-diagnosed, especially in children. The aim of this study was to clarify the characteristics and pathophysiology of CPSE in children with epilepsy.

SUBJECTS AND METHODS

We retrospectively reviewed the medical records and EEGs of 17 children with epilepsy who were diagnosed as having CPSE by ictal or postictal EEGs to investigate clinical and EEG features.

RESULTS

The ages at diagnosis of CPSE ranged from 3 months to 17 years. At the time of diagnosis of CPSE, 13 patients had symptomatic localization-related epilepsy, two had epilepsy with continuous spike-waves during slow wave sleep, and each patient had cryptogenic localization-related epilepsy and idiopathic localization-related epilepsy. Only subtle symptoms including autonomic ones associated with disturbance of consciousness were the main clinical features in 12 of 44 CPSE episodes. Another 22 episodes showed minor focal motor elements, and the other 10 had major convulsive phase during or immediately before CPSE. Ictal EEGs of CPSE were divided into three types according to the degree of high-voltage slow waves (HVS) and spike components. Ictal EEGs could show spike-dominant or spike and HVS mixed patterns even if patients showed only subtle symptoms. The epileptogenic areas estimated by the ictal or postictal EEGs showed variability with only two cases of temporal origin.

CONCLUSION

The close observation of clinical symptoms such as various subtle symptoms and/or mild convulsive elements and ictal EEGs are absolutely needed for the diagnosis of CPSE in children.

[Case of Sturge-Weber syndrome manifesting complex partial status epilepticus]

A three-year-old boy presented with status epilepticus with right hemiconvulsion and complex partial status epilepticus (CPSE) that were preceded by disturbance of consciousness and right hemiplegia just after a traumatic head injury. He was diagnosed as Sturge-Weber syndrome (SWS) because of the presence of a small cutaneous port-wine nevus and the nature of his MRI findings. The nevus was located in the middle of the forehead and was light in color. Intravenous drip infusion of lidocaine was effective for the treatment of CPSE, but the patient has experienced refractory complex partial seizures since then. It has not yet been reported that patients with SWS developed CPSE following head trauma, although it is known that patients with SWS can manifest convulsive status epilepticus. CPSE should be recognized as one of the seizure types of SWS.

Effectiveness of lidocaine infusion for status epilepticus in childhood: a retrospective multi-institutional study in Japan

We evaluated the usefulness of intravenous lidocaine therapy for managing of status epilepticus (SE) during childhood in a retrospective multi-institutional study. Questionnaires were sent to 28 hospitals concerning patients admitted for SE who were managed with lidocaine, assessing patient characteristics, treatment protocols and efficacy. In 279 treated patients, 261 SE occurrences at ages between 1 month and 15 years were analyzed. SE was classified as showing continuous, clustered, or frequently repeated seizures. Considering efficacy and side effects in combination, the usefulness of lidocaine was classified into six categories: extremely useful, useful, slightly useful, not useful, associated with deterioration, or unevaluated. In 148 SE cases (56.7%), lidocaine was rated as useful or extremely useful. Multivariate analysis indicated lidocaine was to be useful in SE with clustered and frequently repeated seizures, and SE attributable to certain acute illnesses, such as convulsions with mild gastroenteritis. Efficacy was poor when SE caused by central nervous system (CNS) infectious disease. Standard doses (approximately 2mg/kg as a bolus, 2mg/kg/h as maintenance) produced better outcomes than lower or higher doses. Poor responders to the initial bolus injection of lidocaine were less likely to respond to subsequent continuous infusion than good initial responders. We recommend lidocaine for use in SE with clustered or frequently repeated seizures, and in SE associated with benign infantile convulsion and convulsions with mild gastroenteritis. Lidocaine should be initiated with a bolus of 2mg/kg. If SE is arrested by the bolus, continuous maintenance infusion should follow; treatment should proceed to different measures when SE shows a poor response to the initial bolus of lidocaine.