Scalp EEG-recorded high-frequency oscillations can predict seizure activity in Panayiotopoulos syndrome.

OBJECTIVE: We studied the relationship between the clinical course of Panayiotopoulos syndrome (PS) and high-frequency oscillations (HFOs) captured during interictal scalp electroencephalography (EEG) to determine the feasibility of using HFOs to detect seizure activity in PS. METHODS: We analyzed the interictal scalp EEGs of 18 children with PS. Age parameters, seizure frequencies, and antiepileptic drugs were compared between the HFO-positive (HFOPG) and HFO-negative (HFONG) groups. RESULTS: Thirteen patients (72.2%) had HFOs while five patients (27.8%) had no HFOs in 194 interictal EEG records. We found no statistically significant differences in the mean age of epilepsy onset and last seizure, seizure frequency, or frequency of status epilepticus. However, the seizure activity period of the HFOPG was significantly longer than that of the HFONG. Patients with an HFO duration longer than 2 years were intractable to treatment. In most cases, seizures did not occur in the absence of HFOs, even when the spikes remained. CONCLUSIONS: HFOs are related to the seizure activity period in patients with PS. SIGNIFICANCE: We propose that HFOs are a biomarker of epileptogenicity and an indicator for drug reduction because seizures did not occur if HFOs disappeared even if the spikes remained.

Clinical and electrophysiological features of acute flaccid myelitis: A national cohort study.

OBJECTIVE: To summarize the neurophysiological properties of acute flaccid myelitis (AFM) and evaluate limb-based motor outcomes. METHODS: Nerve conduction studies (NCS) in 49 patients (21 females, 28 males; median age = 52 m) with AFM (median = 7 d after onset; range 1-122 d) were reviewed. Neurophysiological findings, together with treatment and prognosis, and neurophysiology-neuroimaging correlations were analyzed. RESULTS: The findings indicated that 64% of paralytic limbs during the acute stage (≤14 d after onset) showed diminished or absent compound muscle action potentials (CMAPs), 79% showed normal motor nerve conduction velocities, 55% showed decreased persistence or absent F-waves, and 95% showed normal sensory nerve conduction velocities. The rate of CMAP abnormalities increased from 41% on days 1-2 to 83% on days 13-14. The reduction in CMAP amplitude was correlated with weaker muscle strength at both the peak neurological deficit and the last follow-up. The baseline limb-based muscle strength at nadir and anterior horn-localized magnetic resonance imaging lesions at recovery stage (>14 d) were strong predictors of outcome at the last follow-up. CONCLUSIONS: AFM typically shows neurophysiological features of neuronopathy. SIGNIFICANCE: NCS is probably useful in the diagnosis and evaluation of AFM.

Three-Year Longitudinal Motor Function and Disability Level of Acute Flaccid Myelitis.

BACKGROUND: We summarize the long-term motor outcome and disability level in a cluster of pediatric patients with acute flaccid myelitis (AFM) associated with the enterovirus D68 outbreak in 2015. METHODS: This is a nationwide follow-up questionnaire analysis study. Clinical data including the motor function (manual muscle strength test) and other neurological symptoms were collected at the acute (nadir), recovery (six months), and chronic (three years) stages. We use the Barthel index, which measures 10 variables describing activity of daily living and mobility to assess the disability level. RESULTS: Clinical data of 33 patients with AFM (13 females, 20 males; median age = 4.1 years) were available. Among patients with tetraplegia or triplegia, paraplegia, and monoplegia at the acute stage, two of seven, four of thirteen, and two of thirteen exhibited complete recovery without paralysis; of those five of seven, eight of thirteen, and two of thirteen showed improvement with lesser limb involvement at the chronic stage, respectively. Nine patients (27%) demonstrated improvement at the recovery-to-chronic period. All six patients with positive isolation of enterovirus D68 from biological samples at the acute stage showed persistent motor deficits. Other neurological findings had better prognosis than motor weakness. Better Barthel index score at the chronic stage was observed (P < 0.001; median difference [95% confidence interval], 53 [40 to 63]), implying an improved disability level even in patients with persistent motor deficits. CONCLUSIONS: AFM has a high rate of persistent motor deficits showing one- to two-limb paralysis. Disability level of patients with AFM, however, generally improved at the three-year time point.

Serial MRI findings of acute flaccid myelitis during an outbreak of enterovirus D68 infection in Japan.

OBJECIVE: To clarify the neuroimaging findings of children with acute flaccid myelitis during an outbreak of EV-D68 infection. METHODS: We performed a detailed review of the spinal and cranial MRI results of 54 children with acute flaccid myelitis. We focused on the range of longitudinal lesions, the localization and appearance of lesions within a horizontal section, Gadolinium-enhancement, and changes over time. RESULTS: All children had longitudinal spinal lesions involving central gray matter. Twenty-six children had lesions spanning the entire spine. Six of them had weakness in all limbs, whereas seven had weakness of only one limb. Thirty-eight children had lesions in both gray and white matter and limb weakness tended to be more severe in these children. During the acute period, spinal lesions showed bilateral ill-defined widespread T2 hyperintensity. During the subacute period, lesions were well defined and confined to the anterior horn. The distribution of limb weakness was correlated with the appearance of lesions during the subacute period. Gadolinium enhancement was performed in 37 children, and enhancement was seen in the cauda equina in 29 children. Enhancement was infrequent within 2 days after onset but was seen in almost all children thereafter. Twenty-two children had brainstem lesions continuous with spinal lesions. CONCLUSION: Extensive longitudinal spinal lesions were characteristic in children with acute flaccid myelitis. Lesions were usually bilateral and widespread during the acute period, whereas localization to the anterior horn could become obvious. Although enhancement of the cauda equina was often observed, its appearance was sometimes delayed.

Recurrent autonomic and sensory neuropathy in a patient with anti-ganglionic acetylcholine receptor antibodies.

We report a case of recurrent neuropathy with predominant autonomic and sensory involvement whose serum was positive for anti-ganglionic acetylcholine receptor (anti-gAChR) antibodies, a diagnostic marker of autoimmune autonomic ganglionopathy. An 11-year-old girl complained of numbness and limb pain after gastroenteritis. Although hyperalgesia and autonomic dysfunctions, such as orthostatic intolerance and gastrointestinal dysmotility subsequently developed, these symptoms faded after a few days. Similar sensory and autonomic impairments recurred three times within 12 months after the first episode. The sensory and autonomic symptoms were rapidly ameliorated by the administration of intravenous immunoglobulin (IVIg) at the second and third relapse; however, the symptoms persisted even after the administration of IVIg at the fourth relapse. The residual symptoms disappeared after methylprednisolone pulse therapy. The patient's serum was found to be positive for anti-gAChR antibodies at the second relapse, and was negative after methylprednisolone pulse therapy. Further studies are needed to clarify the efficacy of treatment and the nosological position in the spectrum of neuropathies that are associated with autonomic and sensory impairments.

Long-term efficacy and safety of lamotrigine monotherapy in Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures: An open-label extension study.

PURPOSE: To investigate the efficacy and safety of long-term lamotrigine (LTG) monotherapy in Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures. METHODS: Six Japanese patients and one South Korean patient were enrolled in the extension phase of the study after completing the 12-week maintenance phase of an open-label clinical study of LTG monotherapy. During the extension phase, patients underwent efficacy and safety evaluation every 12 weeks. RESULTS: Of the seven patients, six patients completed the extension phase. The seizure-free rate confirmed by hyperventilation (HV)-electroencephalography ranged from 71.4% to 100.0% at each visit up to Week 168 of the extension phase. Similar effects were confirmed by HV-clinical signs and seizure diaries. Although no unexpected adverse events were observed, one Japanese patient was withdrawn from the extension phase due to mild drug-related rash developed 842 days after the start of LTG. CONCLUSION: Although the number of patients is limited, long-term LTG monotherapy appeared to be effective and generally well tolerated in Japanese and South Korean pediatric patients with typical absence seizures.

Clinical Features of Acute Flaccid Myelitis Temporally Associated With an Enterovirus D68 Outbreak: Results of a Nationwide Survey of Acute Flaccid Paralysis in Japan, August-December 2015.

Background: Acute flaccid myelitis (AFM) is an acute flaccid paralysis syndrome with spinal motor neuron involvement of unknown etiology. We investigated the characteristics and prognostic factors of AFM clusters coincident with an enterovirus D68 (EV-D68) outbreak in Japan during autumn 2015. Methods: An AFM case series study was conducted following a nationwide survey from August to December 2015. Radiographic and neurophysiologic data were subjected to centralized review, and virology studies were conducted for available specimens. Results: Fifty-nine AFM cases (58 definite, 1 probable) were identified, including 55 children and 4 adults (median age, 4.4 years). The AFM epidemic curve showed strong temporal correlation with EV-D68 detection from pathogen surveillance, but not with other pathogens. EV-D68 was detected in 9 patients: 5 in nasopharyngeal, 2 in stool, 1 in cerebrospinal fluid (adult case), and 1 in tracheal aspiration, nasopharyngeal, and serum samples (a pediatric case with preceding steroid usage). Cases exhibited heterogeneous paralysis patterns from 1- to 4-limb involvement, but all definite cases had longitudinal spinal gray matter lesions on magnetic resonance imaging (median, 20 spinal segments). Cerebrospinal fluid pleocytosis was observed in 50 of 59 cases (85%), and 8 of 29 (28%) were positive for antiganglioside antibodies, as frequently observed in Guillain-Barré syndrome. Fifty-two patients showed variable residual weakness at follow-up. Good prognostic factors included a pretreatment manual muscle strength test unit score >3, normal F-wave persistence, and EV-D68-negative status. Conclusions: EV-D68 may be one of the causative agents for AFM, while host susceptibility factors such as immune response could contribute to AFM development.

Lamotrigine monotherapy for newly diagnosed typical absence seizures in children: A multi-center, uncontrolled, open-label study.

PURPOSE: To evaluate the efficacy and safety of lamotrigine (LTG) monotherapy for treating Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures. METHODS: Twenty patients with newly diagnosed typical absence seizures aged 4-12 years were enrolled in the study and were administered LTG at an initial dose of 0.3 mg/kg/day for 2 weeks, followed by 0.6 mg/kg/day for an additional 2 weeks. Thereafter, the dose was increased by 0.6 mg/kg/day up to a maximum of 10.2 mg/kg/day or 400 mg/day (whichever was the lower dose) until patients were confirmed to be seizure free induced by hyperventilation (HV). After confirmation, the dose was increased by one level (0.6 mg/kg/day). If the patient was found to be seizure free by HV-electroencephalography (EEG) on the following two consecutive visits, the patient entered the 12-week maintenance phase. After the maintenance phase, patients could enter the extension phase if clinically indicated. RESULTS: The seizure-free rate confirmed by HV-EEG at the end of the maintenance phase was 35.0% (7/20 patients). Most of patients who were confirmed to be seizure free during the escalation phase had maintained seizure control during the 12-week maintenance phase and the 12-week extension phase. The most frequently noted adverse events were bronchitis, headache, and rash (20% each). No serious adverse events were reported. CONCLUSION: Lamotrigine monotherapy in Japanese and South Korean children with typical absence seizures was well tolerated and 35.0% of patients were seizure free at the end of maintenance phase.

Early onset and focal spike discharges as indicators of poor prognosis for myoclonic-astatic epilepsy.

BACKGROUND: Myoclonic-astatic epilepsy (MAE) is an epileptic syndrome characterized by unique myoclonus, myoclonic-astatic, or astatic seizures in childhood. MAE prognosis vary from spontaneous remission to intractable seizures with profound mental retardation. AIM: Identifying early risk factors may optimize the treatment of children with MAE. Our hypothesis is early onset age and focal spike discharges on EEG indicate a poor MAE prognosis. METHODS: Using the medical records of 9 children with MAE, we analyzed their clinical histories, EEG findings, and seizure symptoms. All patients were given follow-up observations/treatments by our department for at least 2 years after MAE onset. RESULTS: Five of the patients were given favorable prognoses because their seizures disappeared within 2 years of onset; the other 4 received poor prognoses because their seizures continued more than 2 years. MAE onset in patient with refractory seizures was earlier than that in those with a favorable prognosis (7-24 months vs. 23-38 months). All the patients with refractory seizures showed moderate or severe mental retardation. Among the 5 patients with good prognosis, EEGs showed two with focal spike discharges and three with only generalized spike discharges. In contrast, all cases with a poor prognosis had focal spike discharges. CONCLUSIONS: MAE onset in patients with refractory seizures occurs earlier than in those with favorable prognosis. Prognosis was excellent when EEG findings show no focal spike discharges. Both early seizure onset and the focal spike discharges associated with MAE are indicators of poor prognosis.

Genetic analysis of PRRT2 for benign infantile epilepsy, infantile convulsions with choreoathetosis syndrome, and benign convulsions with mild gastroenteritis.

PURPOSE: PRRT2 mutations were recently identified in benign familial infantile epilepsy (BFIE) and infantile convulsions with paroxysmal choreoathetosis (ICCA) but no abnormalities have so far been identified in their phenotypically similar seizure disorder of benign convulsions with mild gastroenteritis (CwG), while mutations in KCNQ2 and KCNQ3 have been recognized in benign familial neonatal epilepsy (BFNE). The aim of this study was to identify PRRT2 mutations in infantile convulsions in Asian families with BFIE and ICCA, CwG and BFNE. METHODS: We recruited 26 unrelated Japanese affected with either BFIE or non-familial benign infantile seizures and their families, including three families with ICCA. A total of 17 Japanese and Taiwanese with CwG, 50 Japanese with BFNE and 96 healthy volunteers were also recruited. Mutations of PRRT2 were sought using direct sequencing. RESULTS: Heterozygous truncation mutation (c.649dupC) was identified in 15 of 26 individuals with benign infantile epilepsy (52.1%). All three families of ICCA harbored the same mutation (100%). Another novel mutation (c.1012+2dupT) was found in the proband of a family with BFIE. However, no PRRT2 mutation was found in either CwG or BFNE. CONCLUSIONS: The results confirm that c.649dupC, a truncating mutation of PRRT2, is a hotspot mutation resulting in BFIE or ICCA regardless of the ethnic background. In contrast, PRRT2 mutations do not seem to be associated with CwG or BFNE. Screening for PRRT2 mutation might be useful in early-stage differentiation of BFIE from CwG.

KCNQ2 abnormality in BECTS: benign childhood epilepsy with centrotemporal spikes following benign neonatal seizures resulting from a mutation of KCNQ2.

The molecular pathogenesis of benign childhood epilepsy with centrotemporal spikes (BECTS) remains unclear whereas mutations of the KCNQ2 and KCNQ3 genes have been identified as causes of benign familial neonatal convulsions. We report here a girl with benign neonatal convulsions followed by BECTS, for whom a mutation of KCNQ2 was identified. This case may provide the clue to the understanding of the molecular pathogenesis of BECTS.

Reduced PLP1 expression in induced pluripotent stem cells derived from a Pelizaeus-Merzbacher disease patient with a partial PLP1 duplication.

Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder characterized by dysmyelination of the central nervous system (CNS). We identified a rare partial duplication of the proteolipid protein 1 gene (PLP1) in a patient with PMD. To assess the underlying effect of this duplication, we examined PLP1 expression in induced pluripotent stem (iPS) cells generated from the patient's fibroblasts. Disease-specific iPS cells were generated from skin fibroblasts obtained from the indicated PMD patient and two other PMD patients having a 637-kb chromosomal duplication including entire PLP1 and a novel missense mutation (W212C) of PLP1, by transfections of OCT3/4, C-MYC, KLF4 and SOX2 using retro-virus vectors. PLP1 expressions in the generated iPS cells were examined by northern blot analysis. Although PLP1 expression was confirmed in iPS cells generated from two patients with the entire PLP1 duplication and the missense mutation of PLP1, iPS cells generated from the patient with the partial PLP1 duplication manifesting a milder form of PMD showed null expression. This indicated that the underlying effect of the partial PLP1 duplication identified in this study was different from other PLP1 alterations including a typical duplication and a missense mutation.

Magnetic resonance imaging volumetry and clinical analysis of epilepsy patients with unilateral hippocampal abnormality.

BACKGROUND: In order to clarify the correlation between morphological characteristics and clinical features in epilepsy patients with unilateral hippocampal abnormality, morphological and morphometric magnetic resonance imaging studies were performed. METHODS: We selected a series of childhood-onset epilepsy patients with unilateral hippocampal abnormality. The volume of hippocampal formation and anterior temporal lobe were measured, and the hippocampal morphology was compared with their clinical features. The morphological characteristics of the hippocampal formation were classified into three groups: group I, diffuse and severe volume reduction of the hippocampal formation and anterior temporal lobe with abnormal signal; group II, focal atrophy or focal abnormal signal in the hippocampal formation; and group III, no significant volume reduction but an enlargement of the temporal horn. RESULTS: All of the patients in group I had a history of status epilepticus in infancy. Temporal lobe epilepsy (TLE) was found in three of four patients. Group II contained TLE in three and frontal lobe epilepsy in one. One patient with intractable TLE had a history of status epilepticus in infancy. Group III contained miscellaneous epilepsies, including benign partial epilepsy with centro-temporal spikes in three of seven patients. Five patients in group III showed some characteristic features of hippocampal malrotation, which refers to incomplete hippocampal infolding. CONCLUSIONS: Diffuse and severe volume reduction of the hippocampal formation and anterior temporal lobe with unilateral hippocampal sclerosis was strongly associated with status epilepticus in infancy. Both hippocampal sclerosis and hippocampal malrotation suggest significant roles in the pathogenesis of epilepsy.

Clinical spectrum of SCN2A mutations.

Mutations in SCN2A, the gene encoding α2 subunit of the neuronal sodium channel, are associated with a variety of epilepsies: benign familial neonatal-infantile seizures (BFNIS); genetic epilepsy with febrile seizures plus (GEFS+); Dravet syndrome (DS); and some intractable childhood epilepsies. More than 10 new mutations have been identified in BFNIS, all of them are missense. To date, only one nonsense mutation has been found in a patient with intractable childhood epilepsy and severe mental decline. Recently, microduplication of chromosome 2q24.3 (containing eight genes including SCN2A, SCN3A, and the 3' end of SCN1A) was reported in a family with dominantly inherited neonatal seizures and intellectual disability. Functional studies of SCN2A mutations show that they can cause divergent biophysical defects in Na(V)1.2 and impair cell surface expressions. There is no consistent relationship between genotype and phenotype.

PCDH19 mutation in Japanese females with epilepsy.

PURPOSE: To determine the significance of PCDH19 mutations in Japanese females with epilepsy and to delineate their phenotypes. METHODS: PCDH19 sequencing analysis was performed in 116 females with various epilepsies, including 97 with Dravet syndrome (83.6%). They were referred for SCN1A analysis, and 52 carried SCN1A mutations. RESULTS: Seven heterozygous mutations in exon 1 were identified in 7 patients (6.0%): 2 frameshift, 2 nonsense, and 3 missense mutations. One patient was a monozygotic twin, and her sister with mild phenotype carried the same mutation. The main clinical features among these 8 patients included early seizure onset (≤25 months of age), seizure clusters (7/8), fever-associated seizures (7/8), single seizure type (6/8), and late deterioration of intellect (5/8). Seizure durations were generally up to a few minutes, and only one patient developed status epilepticus once. The main seizure types were generalized tonic-clonic (4/8), tonic (3/8) and focal seizures, with (2/8) or without secondary generalization (3/8). Myoclonic, atonic and absence seizures were extremely rare. Two patients had Dravet syndrome (25%), and this proportion was significantly smaller than that in the total subjects (p<0.01). CONCLUSION: PCDH19 mutation is a relatively frequent cause of epilepsy in Japanese females. Dravet syndrome was rare in our cohort.

Diagnosing nocturnal frontal lobe epilepsy: a case study of two children.

We describe two children of nocturnal frontal lobe epilepsy (NFLE) diagnosed using carefully observed nocturnal sleep EEGs and detailed patient histories. Case #1, a 14-year-old boy, showed repeated generalized tonic convulsions and frequent eyes opening seizures during sleep. Conventional EEGs - done with the patient awake or in sleep stage I - showed no abnormalities, while a nocturnal sleep EEG - done during in sleep stage II - revealed the repeated, sharp wave bursts predominantly in the right frontal lobe characteristic of NFLE. During these wave bursts, we noticed the boy's eyes opening, although his parents had not been aware this NFLE symptom. Case #2, a 12-year-old boy, showed one daytime generalized convulsion. He had also been suffering from repeated paroxysmal episodes similar to parasomnia - waking up, sitting, walking, screaming, and speaking - which always followed the same patterns lasting several minutes. During the nocturnal sleep EEG, episodes occurred twice, showing abnormal epileptic discharges predominantly in the frontal lobe. His parents did not mention the episodes to us until questioned, as they had recognized them as parasomnia. The previous conventional EEG showed abnormal slow waves in the frontal lobe, which led us to suspect frontal lobe epilepsy and to take a detailed patient history. The frequency and stereotypy of their symptoms during sleep caused us to perform nocturnal sleep EEGs and led us NFLE diagnosis. Detailed patient histories including sleep habits and carefully observed nocturnal sleep EEGs enabled us to recognize these NFLE clinical features.

Mutational analysis of GABRG2 in a Japanese cohort with childhood epilepsies.

A few mutations in the gene encoding the gamma 2 subunit of the gamma-aminobutyric acid receptor type A (GABRG2) have been reported in various types of epilepsy. The aim of this study is to investigate the role of GABRG2 in the pathogenesis of childhood epilepsy in a large Japanese cohort. Genetic analysis of GABRG2 was performed on 140 Japanese patients with various childhood epilepsies largely including Dravet syndrome and genetic epilepsy with febrile seizures plus. The mutational analysis identified one novel missense mutation of GABRG2 (c.236A>G: p.N40S) in a patient with generalized tonic-clonic seizures (GTCS). The mutation was heterozygous and replacing a highly conserved Asn residue with a Ser. The affected amino acid was located at residue 40 of the mature GABRG2 protein, which was near the first one of two high-affinity benzodiazepine-binding domains of the gamma2 subunit (Lys-41-Trp-82). This mutation in such an important position may hamper the function of the channel and contribute to the case's pathogenesis of GTCS.

Clinical study of childhood acute disseminated encephalomyelitis, multiple sclerosis, and acute transverse myelitis in Fukuoka Prefecture, Japan.

Acute disseminated encephalomyelitis (ADEM) has recently been studied in several countries owing to the development and wide spread use of imaging technology, but few epidemiological studies of childhood ADEM have been undertaken in Asian countries. To perform a comprehensive survey of ADEM and related diseases in Japanese children, we conducted a multicenter, population-based study on childhood ADEM, multiple sclerosis, and acute isolated transverse myelitis in Fukuoka Prefecture, Japan. We identified 26 children with ADEM, 8 with multiple sclerosis, and 4 with acute transverse myelitis during 5 years between September 1998 and August 2003. The incidence of childhood ADEM under the age of 15 years was 0.64 per 100,000 person-years, mean age at onset was 5.7 years, and male-female ratio was 2.3:1. The prevalence of childhood multiple sclerosis was 1.3 per 100,000 persons. The mean age at onset of multiple sclerosis, 9.3 years, was significantly higher than that of ADEM. Nineteen (73%) and four (15%) patients with ADEM experienced antecedent infectious illnesses and vaccinations, respectively, within 1 month before the onset. Clinical and radiological findings of ADEM revealed that the frequency of seizures, mean white blood cell counts in cerebrospinal fluid, and the frequency of subcortical lesions in Fukuoka study, seemed to be higher than those in previous non-Asian studies. These findings suggest that there are ethnic or geographical differences in the incidence and clinical features of ADEM, and that there might be potent genetic or environmental risk factors for ADEM distinct from those for multiple sclerosis.