Long-term safety and effectiveness of stiripentol in patients with Dravet syndrome: Interim report of a post-marketing surveillance study in Japan

BACKGROUND

A post-marketing surveillance study is investigating the safety and effectiveness of stiripentol during real-world clinical use in Japanese patients with Dravet syndrome (DS).

METHODS

The safety and effectiveness of stiripentol were prospectively investigated over 104 weeks in all patients with DS who were administered the drug from November 2012 through July 2019 in Japan. Patients administered stiripentol for the first time after its approval were defined as "new patients," and those who continued to take the drug after participating in domestic clinical studies were defined as "continuous-use patients." The responder rate was defined as the proportion of patients with a ≥50 % decrease in seizure episodes at the time of assessment of stiripentol effectiveness compared with the 4 weeks before starting stiripentol. Overall improvement was evaluated by the physician in charge based on the comprehensive assessment of the patient's condition after stiripentol treatment.

RESULTS

Of 411 patients whose information was collected, 410 patients (376 new and 34 continuous-use) were included in the safety analysis set, and 409 (376 new and 33 continuous-use) were included in the effectiveness analysis set. The median age of new patients was 7 years (range: 0.5-50 years) at the time of stiripentol initiation; 99 % of patients were taking concomitant sodium valproate and 93 % clobazam. Adverse drug reactions occurred in 70 % of new patients; the most common were somnolence (39 %) and loss of appetite (25 %). No new safety concerns due to stiripentol were observed. The responder rate in new patients was 43 % (110/257 patients) for convulsive seizures (tonic-clonic and/or clonic convulsions), 55 % (58/105 patients) for focal impaired awareness seizures, and 62 % (56/90 patients) for generalized myoclonic seizures and/or generalized atypical absence seizures. Overall improvement (after 104 weeks or at the time of drug discontinuation) was rated as marked or moderate in 160/353 of new patients (45 %).

CONCLUSION

Stiripentol is safe and effective during long-term use in patients with DS in routine clinical practice.

[Efficacy and Safety of Lorazepam Intravenously Administered in Subjects with Status Epilepticus or Repetitive Seizures]

We evaluated the efficacy and safety of lorazepam (LZP) 4 mg for adults (age, 16 years old or older) or 0.05mg/kg for children (age, 3 months to less than 16 years) as a slow intravenous injection in 26 Japanese patients with status epilepticus or repetitive seizures. The proportion of patients whose initial seizure stopped within 10 minutes and who continued seizure-free for at least 30 minutes after the completion of initial dose as the primary endpoint was 48.0% (12/25, 95%CI: 27.8%-68.7%). However, the proportion of patients whose seizures stopped within 10 minutes and who continued seizure-free for at least 30 minutes after the completion of either initial or second dose (in 10 to 30 minutes from the initial dose) was 64.0% (16/25, 95%CI: 42.5%-82.0%) in total, and 77.8% and 56.3% in adults and children, respectively. The most common adverse events (AEs) were somnolence (7.7%) and insomnia (7.7%), and almost all AEs were mild or moderate in severity. No patient experienced serious or severe LZP-related AEs. No one discontinued the study due to AEs.

Adjunctive levetiracetam in the treatment of Chinese and Japanese adults with generalized tonic-clonic seizures: A double-blind, randomized, placebo-controlled trial

Objective

To assess the efficacy, safety, and tolerability of adjunctive levetiracetam (LEV) in Chinese and Japanese adults with generalized tonic-clonic (GTC) seizures (N01159; NCT01228747).

Methods

This double-blind, randomized, placebo-controlled, multicenter phase III trial comprised: 4-week retrospective and 4-week prospective baseline, 12-week dose-adjustment, and 16-week evaluation periods. Chinese and Japanese patients ≥16 years old with idiopathic generalized, symptomatic generalized, or undetermined epilepsy with GTC seizures received a single-blind placebo during the prospective baseline, and then were randomized 1:1 to placebo or LEV 1,000 mg/day administered twice daily. Patients reporting GTC seizures up to week 8 had the LEV dosage increased to 3,000 mg/day. The primary efficacy variable was percent reduction from combined baseline in GTC seizures/week during the 28-week treatment period.

Results

Overall, 251 patients were randomized (208 from China; 43 from Japan); 141 (56.2%) completed the 28-week treatment period. Least-squares mean percent reduction from combined baseline in GTC seizures/week (treatment period) was placebo 12.6% versus LEV 68.8% (95% confidence interval, 44.0-68.2; p < 0.0001). GTC seizure frequency reduction occurred in both patients with idiopathic and symptomatic generalized epilepsy. The 50% responder rate (treatment period) was placebo 28.4% versus LEV 77.8%. Freedom from GTC seizures (evaluation period) was placebo 3.1% versus LEV 29.6%. Incidence of treatment-emergent adverse events (TEAEs; treatment period) was placebo 52.0% versus LEV 57.1%; most frequently nasopharyngitis, protein in urine, decreased platelet count, and pyrexia. Incidence of TEAEs leading to discontinuation was 4.8% versus 3.2%; incidence of serious TEAEs was 3.2% versus 0.8% for placebo and LEV, respectively; 3 patients taking placebo died versus none taking LEV.

Significance

In this trial, adjunctive LEV 1,000-3,000 mg/day was effective in reducing GTC seizure frequency in Chinese and Japanese patients ≥16 years old with GTC seizures. Seizure reduction occurred in both patients with idiopathic and symptomatic generalized epilepsy. LEV was well tolerated in this population.

Predicting the reading skill of Japanese children

OBJECTIVE

To clarify cognitive processes underlining the development of reading in children speaking Japanese as their first language, we examined relationships between performances of cognitive tasks in the preschool period and later reading abilities.

METHODS

Ninety-one normally developing preschoolers (41 girls and 50 boys; 5years 4months to 6years 4months, mean 5years 10months) participated as subjects. We conducted seven cognitive tasks including phonological awareness tasks, naming tasks, and working memory tasks in the preschool period. In terms of reading tasks, the hiragana naming task was administered in the preschool period; the reading times, which is a composite score of the monomoraic syllable reading task, the word and the non-word reading tasks, and the single sentence reading task, was evaluated in first and second grade; and the kanji reading task (naming task) was tested in second grade. Raven's colored progressive matrices and picture vocabulary test revised were also conducted in first grade. Correlation analyses between task scores and stepwise multiple regression analyses were implemented.

RESULTS

Tasks tapping phonological awareness, lexical access, and verbal working memory showed significant correlations with reading tasks. In the multiple regression analyses the performances in the verbal working memory task played a key role in predicting character naming task scores (the hiragana naming task and the kanji reading task) while the digit naming task was an important predictor of reading times. Unexpectedly, the role of phonological (mora) awareness was modest among children speaking Japanese.

CONCLUSION

Cognitive functions including phonological awareness, digit naming, and verbal working memory (especially the latter two) were involved in the development of reading skills of children speaking Japanese.

Predictive factors for relapse of epileptic spasms after adrenocorticotropic hormone therapy in West syndrome

PURPOSE

To investigate whether serial electroencephalographic (EEG) findings can predict relapse of epileptic spasms after synthetic adrenocorticotropic hormone (ACTH) therapy in patients with West syndrome (WS).

SUBJECTS AND METHODS

Thirty-nine WS patients (8 cryptogenic and 31 symptomatic) were included in this study. These patients received ACTH therapy for the first time and were regularly followed up for more than three years at our hospital. Sixteen patients (41.0%) showed seizure relapse (relapse group) and 23 patients (59.0%) did not show relapse (non-relapse group). We used survival analysis to investigate the influence of etiology and presence of epileptic discharges after the ACTH therapy on seizure outcome.

RESULTS

Immediately after the ACTH therapy, etiology was associated with seizure outcome (p=0.003). In the early stage (1 month after the ACTH therapy), only the presence of epileptic discharges (p=0.001) had a significant association with seizure outcome, regardless of etiology. Because all relapsed patients were in the symptomatic group, we performed the same statistical analysis on symptomatic WS patient data only. We found that the group with no epileptic discharges on EEG showed a significantly higher seizure-free rate than those with epileptic discharges in the early stage (p=0.0091).

CONCLUSION

This study demonstrated that serial EEG findings after ACTH therapy are significantly related to relapse of epileptic spasms.

Occurrence of bilaterally independent epileptic spasms after a corpus callosotomy in West syndrome

We report a patient with intractable West syndrome whose epileptic spasms (ESs) were initially bilaterally synchronous, as is typical; after a complete corpus callosotomy, however, bilaterally independent ESs originated in either hemisphere. Activity of probable cortical origin associated with ESs was detected by observing ictal gamma oscillations. Brain MRI revealed no structural abnormality before surgery. This case suggests that ESs with a hemispheric origin may appear generalized because of synchronizing effects in the corpus callosum in some patients.

A high incidence of WT1 abnormality in bilateral Wilms tumours in Japan, and the penetrance rates in children with WT1 germline mutation

Background:

Bilateral Wilms tumours (BWTs) occur by germline mutation of various predisposing genes; one of which is WT1 whose abnormality was reported in 17–38% of BWTs in Caucasians, whereas no such studies have been conducted in East-Asians. Carriers with WT1 mutations are increasing because of improved survival.

Methods:

Statuses of WT1 and IGF2 were examined in 45 BWTs from 31 patients with WT1 sequencing and SNP array-based genomic analyses. The penetrance rates were estimated in WT1-mutant familial Wilms tumours collected from the present and previous studies.

Results:

We detected WT1 abnormalities in 25 (81%) of 31 patients and two families, which were included in the penetrance rate analysis of familial Wilms tumour. Of 35 BWTs from the 25 patients, 31 had small homozygous WT1 mutations and uniparental disomy of IGF2, while 4 had large 11p13 deletions with the retention of 11p heterozygosity. The penetrance rate was 100% if children inherited small WT1 mutations from their fathers, and 67% if inherited the mutations from their mothers, or inherited or had de novo 11p13 deletions irrespective of parental origin (P=0.057).

Conclusions:

The high incidence of WT1 abnormalities in Japanese BWTs sharply contrasts with the lower incidence in Caucasian counterparts, and the penetrance rates should be clarified for genetic counselling of survivors with WT1 mutations.

High-frequency EEG activity in epileptic encephalopathy with suppression-burst

OBJECTIVE

We explored high-frequency activity in the suppression-burst (SB) pattern of interictal electroencephalogram (EEG) in early infantile epileptic encephalopathy including Ohtahara syndrome (OS) and early myoclonic encephalopathy (EME) to investigate the pathophysiological characteristics of SB.

METHODS

Subjects included six patients with the SB EEG pattern related to OS or EME (Group SB). The results were evaluated in comparison to tracé alternant (TA) observed during the neonatal period in nine patients to rule out possible nonspecific relationships between high-frequency activity and periodic EEG patterns (Group TA). EEG was digitally recorded with a sampling rate of 500Hz and the analysis was performed in each of the particular bipolar channel-pairs. We visually selected 20 typical consecutive burst sections and 160 inter-burst sections for comparison from the sleep record of each patient and performed the time-frequency analysis. We investigated the maximum frequencies of power enhancement in each derivation in both groups.

RESULTS

In Group SB, a significant increase in power at a frequency of 80-150Hz was observed in association with the bursts, particularly in the bilateral parieto-occipital derivations, in all patients. In Group TA, on the contrary, no significant increase in high-frequency power was found. The maximum frequencies of power enhancement were significantly higher in Group SB than in Group TA (p<0.001 by repeated-measures ANOVA).

CONCLUSION

Interictal high frequencies of up to 150Hz were detected in the suppression-burst EEG patterns in epileptic encephalopathy in early infancy. Further studies will be necessary to identify the role of the interictal high-frequency activity in the pathophysiology of such early epileptic encephalopathy.

Autosomal recessive cystinuria caused by genome-wide paternal uniparental isodisomy in a patient with Beckwith-Wiedemann syndrome

Approximately 20% of Beckwith-Wiedemann syndrome (BWS) cases are caused by mosaic paternal uniparental disomy of chromosome 11 (pUPD11). Although pUPD11 is usually limited to the short arm of chromosome 11, a small minority of BWS cases show genome-wide mosaic pUPD (GWpUPD). These patients show variable clinical features depending on mosaic ratio, imprinting status of other chromosomes, and paternally inherited recessive mutations. To date, there have been no reports of a mosaic GWpUPD patient with an autosomal recessive disease caused by a paternally inherited recessive mutation. Here, we describe a patient concurrently showing the clinical features of BWS and autosomal recessive cystinuria. Genetic analyses revealed that the patient has mosaic GWpUPD and an inherited paternal homozygous mutation in SLC7A9. This is the first report indicating that a paternally inherited recessive mutation can cause an autosomal recessive disease in cases of GWpUPD mosaicism. Investigation into recessive mutations and the dysregulation of imprinting domains is critical in understanding precise clinical conditions of patients with mosaic GWpUPD.

Inhibitory function and working memory in attention deficit/hyperactivity disorder and pervasive developmental disorders: does a continuous cognitive gradient explain ADHD and PDD traits?

To clarify the relationship between attention deficit/hyperactivity disorder (AD/HD) and pervasive developmental disorders (PDD), we investigated the common features and differences of these disorders in neuropsychological profiles. The subjects were 4 groups of Japanese boys aged 6 to 15 years, categorized by diagnosis:AD/HD (n＝20), PDD with comorbid AD/HD (PDD＋:n＝16), PDD without comorbid AD/HD (PDD－:n＝8), and typically developing (n＝60). We evaluated executive function (EF) through verbal and visuospatial memory tasks, the Go/NoGo task, and the color-word matching Stroop task. We performed a categorical analysis to estimate the effects of the 3 disorders on EF and a dimensional analysis to estimate the effects of symptom scales on EF. We found that the AD/HD and PDD＋ subjects had negative effects on verbal working memory and intra-individual response variability. The severity of these impairments was positively correlated with the inattentiveness score. The subjects with a PDD＋ or PDD－ diagnosis had poorer scores on interference control;the severity of this impairment was correlated with the PDD symptom score. Impairments in visuospatial working memory were detected in the AD/HD and PDD－ groups but not in the PDD＋ group. Impairments in inhibition of the pre-potent response were noted in all 3 categories. AD/HD and PDD share neuropsychological features, though each disorder has a specific impairment pattern. Our findings partially support the idea that AD/HD and PDD are on a spectrum.

Ultrafast time-resolved magneto-optical imaging of all-optical switching in GdFeCo with femtosecond time-resolution and a μm spatial-resolution

We developed an ultrafast time-resolved magneto-optical (MO) imaging system with several millidegree resolution of light polarization angle, 100 fs time-resolution, and a micrometer spatial resolution. A CCD camera with about 10(6) pixels is used for detection and MO images with an absolute angle of the light polarization are acquired by the rotating analyzer method. By optimizing the analysis procedure with a least square method and the help of graphical processor units, this novel system significantly improves the speed for MO imaging, allowing to obtain a MO map of a sample within 15 s. To demonstrate the strength of the technique, we applied the method in a pump-and-probe experiment of all-optical switching in a GdFeCo sample in which we were able to detect temporal evolution of the MO images with sub-picosecond resolution.

[New antiepileptic drugs: characteristics and clinical applications]

New antiepileptic drugs (AEDs) that have been used in many other countries for more than 10 years have only recently became available for use in Japan. Gabapentin, topiramate, lamotrigine and levetiracetam were licensed for use in Japan between 2006 and 2010. Stiripentol for Dravet syndrome and rufinamide for Lennox-Gastaut syndrome were also approved in 2012 and 2013 as orphan drugs. Clinical trials of other new AEDs such as oxcarbazepine, vigabatrin, lacosamide, and perampanel are in progress. In this review, the general characteristics of the new AEDs are discussed with regards to their effectiveness, tolerability, drug interaction, safety and mechanisms of action. The effectiveness, of the new AEDs compared with established AEDs is also discussed. Clinical applications of the new AEDs, focusing on gabapentin, topiramate, lamotrigine and levetiracetam are also discussed based on our domestic experience as well as overseas reports.

A novel de novo point mutation of the OCT-binding site in the IGF2/H19-imprinting control region in a Beckwith-Wiedemann syndrome patient

The IGF2/H19-imprinting control region (ICR1) functions as an insulator to methylation-sensitive binding of CTCF protein, and regulates imprinted expression of IGF2 and H19 in a parental origin-specific manner. ICR1 methylation defects cause abnormal expression of imprinted genes, leading to Beckwith-Wiedemann syndrome (BWS) or Silver-Russell syndrome (SRS). Not only ICR1 microdeletions involving the CTCF-binding site, but also point mutations and a small deletion of the OCT-binding site have been shown to trigger methylation defects in BWS. Here, mutational analysis of ICR1 in 11 BWS and 12 SRS patients with ICR1 methylation defects revealed a novel de novo point mutation of the OCT-binding site on the maternal allele in one BWS patient. In BWS, all reported mutations and the small deletion of the OCT-binding site, including our case, have occurred within repeat A2. These findings indicate that the OCT-binding site is important for maintaining an unmethylated status of maternal ICR1 in early embryogenesis.

Cortical contribution to scalp EEG gamma rhythms associated with epileptic spasms

The cortical contribution for the generation of gamma rhythms detected from scalp ictal EEG was studied in unique cases of epileptic spasms and a review of the related literature was conducted. Ictal scalp gamma rhythms were investigated through time-frequency analysis in two cases with a combination of focal seizures and spasms and another case with spasms associated with cortical dysplasia. In the two patients with combined seizures, the scalp distribution of ictal gamma rhythms was related to that of focal seizure activity. In the third patient, an asymmetric distribution of the ictal scalp gamma rhythms was transiently revealed in correspondence to the dysplasic cortex during hormonal treatment. Therefore, the dominant region of scalp gamma rhythms may correspond to the epileptogenic cortical area. The current findings have reinforced the possibility of the cortical generation of ictal scalp gamma rhythms associated with spasms. The detection of high frequencies through scalp EEG is a technical challenge, however, and the clinical significance of scalp gamma rhythms may not be the same as that of invasively recorded high frequencies. Further studies on the pathophysiological mechanisms related to the generation of spasms involving high frequencies are necessary in the future, and the development of animal models of spasms will play an important role in this regard.

Dravet syndrome: a genetic epileptic disorder

Dravet syndrome (DS), or severe myoclonic epilepsy in infancy, is one of the most severe types of genetic epilepsy. It is characterized by the initial occurrence of febrile or afebrile seizures that often evolve into status epilepticus in infants with normal development, and by the subsequent appearance of myoclonic and/or atypical absence seizures as well as complex partial seizures. The key feature that characterizes DS is fever sensitivity, although photosensitivity and pattern-sensitivity are also often seen. The prognosis is unfavorable in most cases. Seizures become drug-resistant and persist, with many patients suffering from motor and cognitive impairment. Mutations of SCN1A, which encodes the voltage-gated sodium channel NaV1.1, are the most frequent genetic cause of this syndrome. SCN1A mutations and/or microchromosomal rearrangements involving SCN1A are detected in about 85ｵ of patients. Mutations of PCDH19 have also been reported in female patients with clinical findings compatible with DS. PCDH19 mutations might account for 5ｵ of overall DS cases. Thirty years after its first description, DS is considered as a model of channelopathy. This survey reviews recent developments in the research literature on DS, focusing on the clinical course, as well as its genetic causes.

Relationships between the color-word matching Stroop task and the Go/NoGo task: toward multifaceted assessment of attention and inhibition abilities of children

Both selective attention and response inhibition can be assessed through the Stroop task and the Go/NoGo task (Go/NoGo). The color-word matching Stroop task (cwmStroop) differs from the traditional Stroop task in ways that make it easy to administer, and it enables the examiners to analyze reaction time. It is expected that the cwmStroop and Go/NoGo tasks will be useful as clinical assessments for children with developmental disorders and in combination with functional magnetic resonance imaging studies. The objectives of this study were to elucidate the pattern of developmental change in cwmStroop scores and Go/NoGo scores and to determine whether and how cwmStroop scores are related to Go/NoGo scores. The subjects consisted of 108 healthy Japanese children aged 6-14 years. We found that cwmStroop and Go/NoGo scores displayed clear developmental changes between 6 and 14 years of age. The children's scores on the 2 tasks followed different developmental courses, however, and the correlation between scores on the two tasks was weak on the whole. These results indicate that the cwmStroop and Go/NoGo tasks tap different aspects of selective attention and response inhibition. Therefore it is expected that the combination of both tests will be useful in the multifaceted assessment of selective attention and response inhibition in childhood.

Effects of intravenous diazepam on high-frequency oscillations in EEGs with CSWS

High-frequency oscillations (HFOs) associated with continuous spike-waves during slow-wave sleep (CSWS) are speculated to be linked to the disturbance of higher brain function. We intended to investigate the generative mechanisms of HFOs in CSWS by clarifying the effects of intravenous injection (IV) of diazepam (DZP), an agonist for the gamma-aminobutyric acid A (GABAA) receptor in the GABAergic interneuron system, in patients who had previously been treated with IV DZP. The subjects were three patients with epilepsy with CSWS. For each patient, EEG data before and after IV DZP were separated into consecutive 5-min sections. Time-frequency power spectral analysis was performed on the spikes of each section, and peak-power and frequency of detected high-frequency spectral spots were compared before and after IV DZP. Spectral spots with peak-frequencies at 85.9-121.1Hz in the ripple band were revealed in all three patients. Although the amplitudes of the spikes largely returned to the baseline levels 20-25min after IV DZP, the recovery of the peak-power levels of HFOs lagged behind that of the spike amplitudes, and the power levels of HFOs were lower than the baseline data within 25min after the injection of DZP. No consistent changes were found regarding the spectral frequencies of HFOs. The dissociation of the effect of IV DZP in terms of recovery when comparing spike-amplitudes and the power of HFOs may correspond to an already suggested difference in the pathophysiological mechanisms that generate the spikes and HFOs.

Clinical implications of preceding positive spikes in patients with benign partial epilepsy and febrile seizures

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.

Questionnaire-based assessment of behavioral problems in Japanese children with epilepsy

Behavioral problems in Japanese children with epilepsy were investigated by means of a questionnaire for parents consisting of three checklists: the Child Behavior Checklist (CBCL)/4-18 Japanese Edition, the High-Functioning Autism Spectrum Screening Questionnaire (ASSQ), and the Attention-Deficit/Hyperactivity Disorder (ADHD) Rating Scale-IV (ADHD-RS) for parents. The participants were the parents of 108 children aged 6-18 years with apparently normal intelligence. The CBCL indicated abnormal behavior in 10.5 to 35.6% of the children, and T scores on both the internalizing and externalizing scales had a significant positive relation with scores on the ASSQ and ADHD-RS. It was revealed through multivariate logistic regression analysis that the persistence of seizures was significantly related with abnormality on the externalizing scale of the CBCL (p=0.010, odds ratio: 3.48, 95% confidence interval: 1.34-9.02). Future studies are needed to determine whether seizure freedom improves behavior in children with epilepsy.

Survey of subacute sclerosing panencephalitis in Japan

Investigators conducted a retrospective epidemiological study of subacute sclerosing panencephalitis, a fatal disease caused by measles infection, over the past few years in Japan. Data on 118 cases obtained from a questionnaire sent to attending physicians were analyzed. The annual incidence of subacute sclerosing panencephalitis was approximately 0.03 cases per million from 2001 to 2005. Children infected with measles at a young age (<12 months) showed a high incidence of subacute sclerosing panencephalitis, and those infected before 6 months of age showed earlier onset. Because a positive correlation was found between the prevalence of measles and the onset of subacute sclerosing panencephalitis, particularly among children infected at an early age, it is vital to eradicate measles infection by vaccination.

[A study of reading disorder comorbid with pervasive developmental disorder or attention-deficit/hyperactivity disorder]

OBJECTIVE

We investigated the frequency and characteristics of reading disorder comorbid with pervasive developmental disorder (PDD) or attention-deficit/hyperactivity disorder (AD/HD).

METHODS

Articulation times and reading errors were evaluated using four Japanese reading tasks (a monomoraic syllable reading task, a word reading task, a non-word reading task, and a short sentence reading task) in 31 children with PDD (22 boys and 9 girls) aged 6-14 years (average 9.5 years) and 39 children with AD/HD (33 boys and 6 girls) aged 6-12 years (average 9.6 years). Poor readers (PRs) were identified when articulation times were significantly longer than those of typically-developing children (> or = 2.0 SD) for two or more reading tasks, and non-PRs were identified when articulation times were within normal range (<2.0 SD) for all reading tasks.

RESULTS

Eight children with PDD (25.8%) and 17 children with AD/HD (43.6%) were identified as PRs. For 13 of the 70 subjects, the chief complaints were difficulties in reading and writing words at their first visit to our hospital. All 13 of these subjects had AD/HD, and twelve of these were additionally identified as PRs. Among the remaining 26 children with AD/HD, five (19.2%) were identified as PRs. In AD/HD children, PRs made significantly more reading errors and had lower IQ scores than did non-PRs, but in PDDchildren, there were no significant differences between these two groups regarding IQ or reading errors. An analysis using the Clinical-Symptoms-Checklist for Reading and Writing Words revealed that PRs in our study showed difficulties in reading words in daily life.

CONCLUSIONS

PRs in our study had reading disorders, which would, in turn, mean that reading disorder was often comorbid with PDD or AD/HD. These results strongly indicate the necessity of testing for the presence of reading disorder in children with PDD or AD/HD.

Intractable absence seizures in hyperinsulinism-hyperammonemia syndrome

A girl with intractable absence seizures and facial myoclonia at age 7 years was eventually diagnosed with hyperinsulinism-hyperammonemia syndrome because of hypoglycemia, hyperinsulinism, hyperammonemia, and the results of an oral l-leucine loading test. Her seizures occurred even during periods of relatively normal blood glucose levels, and were completely suppressed by diazoxide treatment only. Her diagnosis of hyperinsulinism-hyperammonemia syndrome was confirmed by a loss of sensitivity of glutamate dehydrogenase for guanosine 5'-triphosphate. Genetic studies identified the I444M mutation in the GLUD1 gene, which encodes glutamate dehydrogenase. This case illustrates the complex relationship between seizures and hypoglycemia in hyperinsulinism-hyperammonemia syndrome that can create diagnostic difficulties. The possibility of hyperinsulinism-hyperammonemia syndrome should be considered in patients with refractory absence seizures with myoclonia.

Efficacy of topiramate for intractable childhood generalized epilepsy with epileptic spasms: with special reference to electroencephalographic changes

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 ≤ 12 years 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 5 years, 8 months. 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.

[Peculiar involuntary movements in premature babies with specific cerebellar injuries]

We observed characteristic involuntary movements in premature babies during early infancy. These movements consisted of asymmetrical irregular banging of the extremities, similar to chorea, ballisms, or jitteriness. We investigated the clinical characteristics and neuroimaging findings of the patients with these peculiar involuntary movements to clarify their pathophysiological mechanisms and to find a treatment. In our sequential follow-up study on 90 premature infants with various pre-and perinatal brain insults, we found various types of cerebellar injuries in 28 patients. In 19 of these, the prominent injuries were observed in the inferior cerebellar hemispheres. These cerebellar injuries were often observed in patients born before the gestational age of 27 weeks. Fourteen of the 28 patients with cerebellar injuries displayed the above-mentioned characteristic involuntary movements. Twelve of these 14 patients with both cerebellar injury and involuntary movements were born before the gestational age of 27 weeks. On the contrary, 10 patients with cerebellar injury born after the gestational age of 27 weeks did not display these peculiar involuntary movements. It is noteworthy that cerebral injuries were not associated with the occurrence of these involuntary movements. Two patients with asymmetrical cerebellar deformity caused by compression due to a cystic lesion did not show these involuntary movements. The movements appeared around the corrected age of 3 months, and they disturbed the patients' acquisition of sitting ability. Nine patients with these involuntary movements developed severe athetotic cerebral palsy. These movements showed drug resistance, however, benzodiazepines had a partial effect in some patients. Recently, cerebellar injury in premature infants has received a lot of attention. We believe that the peculiar involuntary movements we observed in the present patient group may be caused by a particular type of cerebellar damage specific to premature infants born before 27 weeks of gestational age.

Executive function in children with pervasive developmental disorder and attention-deficit/hyperactivity disorder assessed by the Keio version of the Wisconsin card sorting test

The Wisconsin card sorting test (WCST) comprehensively examines executive function (EF). The Keio version of the WCST (KWCST) uses fewer cards and presents them in two steps, separated by a short pause during which an instruction is given. Being of short duration, this test is suitable for children with pervasive developmental disorder (PDD) and attention-deficit/hyperactivity disorder (AD/HD), yet few studies have examined the performance of children with such developmental disorders in the second step of a two-step test such as the KWCST. Using the KWCST, this study compares EF in children with PDD (n=52), or AD/HD (n=46) to that in typically developing (TD) children (n=52). Scores for the six indices of this test, including numbers of response cards until the first category achieved (NUCA), total errors (TE), and non-perseverative errors of Nelson (NPEN), were analyzed using ANOVA. Compared to the TD group, scores in the PDD and/or AD/HD groups were significantly lower for all indices except NUCA and NPEN for the first step, and lower for all indices except NUCA for the second step. Moreover, significantly fewer improvements in TE were seen in the PDD group, and significantly fewer improvements in NPEN were seen in the AD/HD group, compared with TD. This study suggests that both PDD and AD/HD make it difficult for children to utilize their experience in the first step and to effectively apply the instruction given before the second step. It also suggests that the two-step nature of the KWCST is clinically important.

Amelioration of disabling myoclonus in a case of DRPLA by levetiracetam

We report on an 18-year-old male patient with dentatorubral-pallidoluysian atrophy (DRPLA) (number of CAG repeats: 68) with progressive myoclonus epilepsy (PME), who showed a dramatic response to levetiracetam in terms of the intensity of myoclonus. He began to have convulsive seizures and myoclonus at 7 and 10 years of age, respectively, and his intelligence deteriorated from 12 years of age. EEG showed multifocal and diffuse spike-and-wave complexes. His convulsive seizures were suppressed from 13 years of age. At 17 years of age, the patient showed gradual intensification of erratic segmental positive myoclonus as well as frequent atonic falls that were probably attributable to negative myoclonus. Back averaging of EEG data revealed cortical discharges associated with positive myoclonus. Photosensitive myoclonic seizures were also observed. The administration of levetiracetam alleviated positive myoclonus and suppressed atonic falls, resulting in a remarkable improvement in the patient's quality of daily life. Reports on the efficacy of levetiracetam for myoclonus in DRPLA are still rare, though its effect on PME is known in the context of other neurological disorders. Thus levetiracetam should be subjected to clinical trials as a means of disabling myoclonus in DRPLA.

A novel mutation in SCN4A causes severe myotonia and school-age-onset paralytic episodes

Mutations in the pore-forming subunit of the skeletal muscle sodium channel (SCN4A) are responsible for hyperkalemic periodic paralysis, paramyotonia congenita and sodium channel myotonia. These disorders are classified based on their cardinal symptoms, myotonia and/or paralysis. We report the case of a Japanese boy with a novel mutation of SCN4A, p.I693L, who exhibited severe episodic myotonia from infancy and later onset mild paralytic attack. He started to have apneic episodes with generalized hypertonia at age of 11 months, then developed severe episodic myotonia since 2 years of age. He presented characteristic generalized features which resembled Schwarz-Jampel syndrome. After 7 years old, paralytic episodes occurred several times a year. The compound muscle action potential did not change during short and long exercise tests. Functional analysis of the mutant channel expressed in cultured cell revealed enhancement of the activation and disruption of the slow inactivation, which were consistent with myotonia and paralytic attack. The severe clinical features in his infancy may correspond to myotonia permanence, however, he subsequently experienced paralytic attacks. This case provides an example of the complexity and overlap of the clinical features of sodium channel myotonic disorders.

[Lamotrigine add-on therapy for childhood-onset refractory epilepsy: comparison of the efficacy between 3 months and 6 months after initiation]

We investigated the effect of lamotrigine (LTG) add-on therapy in 50 patients with childhood-onset refractory epilepsy (25 males and 25 females): 15 with localization-related epilepsy, 33 with generalized epilepsy, and 2 with undetermined epilepsy. Twenty-four patients had experienced a period of West syndrome during their clinical course. Age at the start of LTG therapy ranged from 2 years 6 months to 41 years 2 months: <16 years in 43 and > or = 16 years in 7. Seizure frequency was > or = 1 per day in 36 patients (72%) and > or = 1 per week in 14 (28%). We increased the LTG dosage every two weeks in accordance with usage recommendations. We evaluated efficacy at two points: 3 and 6 months after the start of LTG. At the 6-month point, seizure freedom was achieved in 2 patients (4%), > or = 50% seizure reduction in 14 (28%), 25 to 50% seizure reduction in 20 (40%), no effect in 6 (12%), and aggravation in 4 (8%). Only 4 patients (8%) stopped LTG therapy within 6 months due to LTG-related mild skin rash in 2 and suspicion of seizure aggravation in the other 2. In terms of seizure types, seizure freedom or > or = 50% seizure reduction was achieved in 29% for epileptic spasms, 32% for tonic seizures, and 29% for partial seizures. A comparison between the 3- and 6-month points revealed that the efficacy level was increased or maintained in 77% of the patients and decreased in 23%. In most cases, the highest level of efficacy appeared within 3 months with doses that were smaller than maintenance doses. Observed CNS-related adverse effects included somnolence in 16 patients, irritability in 14, and sleep disturbance in 11. Positive psychotropic effects in daily activities were seen in 28 patients (56%). These effects appeared regardless of the change in seizure frequency with doses that were smaller than maintenance doses.

Vitamin B(6) treatment of intractable seizures

Vitamin B(6) (VB(6))-related seizures include clinical seizures associated with VB(6) deficiency and dependency. Both types of seizures are suppressed by VB(6). We proposed VB(6)-responsive seizures as the third category of VB(6)-related seizures in 1977. Vitamin B(6)-responsive seizures decrease or disappear in response to high-dose oral VB(6). Seizure onset in most of our cases occurred within the first year of life, although this varied between 3 months and 5 years. Etiologically, such cases were not only idiopathic or cryptogenic, but also symptomatic and associated with organic brain lesions. The tryptophan load test was usually negative. Vitamin VB(6)-responsive seizures or epilepsy were usually West syndrome (WS), however may also include Lennox-Gastaut syndrome, grand mal or partial motor seizures. High-dose VB(6) treatment administered to 216 consecutive WS cases had an overall response rate of 13.9%, being high not only in cryptogenic cases (32%), but also in symptomatic WS (11.5%) associated with identifiable brain pathologies. Notably, responsive patients had excellent long-term seizure and mental outcomes without the need for conventional antiepileptic medication. A gradual increase in clinical response to VB(6) was noted with increasing the VB(6) dose from 30 to 50-100mg/day, and a dramatic increase in clinical response with high-dose VB(6) (100-400mg). Little clinical response was noted with administration of low dose VB(6) (10-30 mg/day). Thus, high-dose oral VB(6) treatment is recommended in all WS patients at time of initial treatment for a minimum of 10 days, considering the safety and rapid onset of efficacy, usually within 1 week, of this treatment.

[Children with attention deficit/hyperactivity disorder and pervasive developmental disorder:attention and response inhibition in the kiddie continuous performance test]

Continuous Performance Test (CPT) is widely used to assess the attention function and response inhibition in both children and adults. This study attempts to examine the performances of boys with attention deficit/hyperactivity disorder (AD/HD) and pervasive developmental disorder (PDD) with and without comorbid AD/HD using a CPT. Among the various versions of the CPT available, we used the Kiddie CPT (K-CPT) modified for younger children. The K-CPT was administered to children with AD/HD (n=22), those with PDD (n=19), and typically developing children (n=41) from 7 to 12 years of age. All children were drug free at the time of examination. The performances were examined in 6 measures:total number of omission errors (OE), total number of commission errors (CE), mean hit reaction time (HRT), hit reaction time standard error (HRTSE), perceptual sensitivity (d'), and response style (beta). Significantly lower scores in d' and a tendency to more errors in CE were found in the AD/HD group compared with the control group. Significantly lower scores in d' and significantly more errors in CE were also found in the PDD group with AD/HD symptoms compared with the control group. Moreover the AD/HD group showed significantly more errors in OE and higher scores in HRTSE compared with the control group. There were no significant group differences between the PDD group without AD/HD symptoms and the control group on all measures. Less favorable scores in AD/HD suggest inadequate selective attention, sustained attention and/or response inhibition. Results of the PDD group with comorbid AD/HD may reflect a basis of AD/HD impairment. Our findings may provide an understanding of neuropsychological characteristics underlying developmental disorders.

[Paroxysmal automatic movements mimicking neonatal seizures induced by midazolam]

We have observed paroxysmal automatic movements including drum-beating and pedaling motions in three full-term neonates following intravenous bolus injections (0.1-0.3 mg/kg/dose) or drip infusions (0.2 mg/kg/h) of midazolam used for sedation. In one patient, abnormal movements were also induced by a bolus injection of midazolam during the EEG recording, and no change was revealed in the EEG during the episode. In another patient, abnormal movements were further worsened by an injection of diazepam. Interictal EEGs of all patients were normal. The clinical manifestations of these paroxysmal automatic movements and the mode of their appearance were quite similar in all patients. It is quite likely that abnormal movements in the patient without ictal EEG change do not have epileptic origin but brainstem release phenomenon induced by midazolam. Because the abnormal movements in the other two cases had similar clinical manifestations and mode of appearance, we suspected that these movements were also non-epileptic though ictal EEGs were not recorded in theses cases. When we encounter paroxysmal automatic movements mimicking neonatal seizures following intravenous midazolam administration, ictal EEG recordings are recommended. If there are no ictal changes, we should avoid treatment with anticonvulsant drugs for these movements. Since midazolam is frequently used in neonates for sedation during various examinations, future investigations on the selection of appropriate drugs and dosage for sedation in neonates, including the usage of midazolam, are necessary.

Reading skills of Japanese second-graders

BACKGROUND

A few studies have explored the prevalence of dyslexia among children who speak Japanese as their native language by evaluating them individually by means of reading-based tasks. The present study was designed to clarify the frequency of suspected dyslexia among second-graders attending ordinary classes.

METHODS

The subjects were 40 children (22 males, 18 females; 7 years 4 months-8 years 4 months; mean age, 7 years 11 months) out of 182 second-graders at a public elementary school situated in a local city. Each subject underwent a monomoraic syllable reading task, a word reading task, a non-word reading task, and a short sentence reading task.

RESULTS

The scores on the four tests were not normally distributed; rather, they were strongly skewed to shorter reading time or fewer reading errors. In addition, they were significantly extended toward either longer reading time or more reading errors. Except in the non-word reading task, most subjects only made a few reading errors. Seven subjects (17.5%) showed at least one score that was more than 1.5 IQR (interquartile range) higher than the third quartile of that subject's eight scores on the four tasks. Assuming that those seven children are potentially dyslexic, at least 3.8% of second-graders (seven out of 182) are suspected to be suffering from dyslexia.

CONCLUSION

It is likely that the prevalence of dyslexia in Japan is comparable to that in Europe and the US. To confirm this, a more comprehensive study on a larger scale should be implemented in the future.

Abnormal fast activity before the onset of West syndrome

In our sequential EEG study performed on 68 infants with various pre- and perinatal brain insults, we found peculiar abnormal fast activity (AFAs) in 12 patients. 9 of the 12 patients with AFAs later developed West syndrome (WS) compared with only 3 of the 56 patients without AFAs (p<0.001, χ(2) test). We analyzed these AFAs using EEG topography, and compared them with ictal fast activity (IFA) corresponding to tonic spasms observed later in the same patients after they had developed WS. We also investigated the clinical and EEG features in these patients. AFAs were first observed commonly at 4-5 months of CA, before the onset of WS. AFA topographic maps revealed posterior predominance in 11 of the 12 patients; IFA maps also showed posterior predominance but were more widely distributed. We propose that, though AFAs and IFAs are different, they share certain aspects of their pathophysiology, and that the maturational process of the occipital cortex plays an important role in the shared aspects. Since AFAs are observed before the onset of WS, they can be considered a sign that WS is imminent.