Mari Akiyama

Focal resection of fast ripples on extraoperative intracranial EEG improves seizure outcome in pediatric epilepsy

Purpose:  High‐frequency oscillations (HFOs), termed ripples at 80–200 Hz and fast ripples (FRs) at >200/250 Hz, recorded by intracranial electroencephalography (EEG), may be a valuable surrogate marker for the localization of the epileptogenic zone. We evaluated the relationship of the resection of focal brain regions containing high‐rate interictal HFOs and the seizure‐onset zone (SOZ) determined by visual EEG analysis with the postsurgical seizure outcome, using extraoperative intracranial EEG monitoring in pediatric patients and automated HFO detection.

Histopathology of cortex and white matter in pediatric epileptic spasms: Comparison with those of partial seizures

Epileptic spasms in older children have increasingly been recognized as a distinct seizure type and subset of these patients are considered for surgical resection. This study compares histopathology and magnetic resonance imaging (MRI), especially focusing the difference between the cortical grey matter and the subcortical white matter to understand the extensive epileptic brain in patients with epileptic spasms. We examined 22 patients consisting of 11 patients with epileptic spasms and 11 with partial seizures. Scalp video electroencephalography (EEG) showed interictal generalized epileptiform discharges (9 patients with epileptic spasms vs. 1 with partial seizures) and ictal generalized epileptiform discharges (10 vs. 3). We found MRI abnormalities in a single lobe (6 vs. 7) and multiple lobes (2 vs. 1). Surgical resections were performed across multiple lobes (9 vs. 2), comparing within a single lobe (2 vs. 9), (p<0.001). Histopathology showed abnormal cortical organizations as FCD (2 vs. 5) and microdysgenesis (4 vs. 4), normal (4 vs. 1). Two patients with epileptic spasms showed hyaline proteoplasmic astrocytopathy. There were heterotopic neurons (10 vs. 10), cluster of oligodendroglia (8 vs. 7), balloon cells (2 vs. 5) and blurred myelination (1 vs. 4), in the white matter. Seizure-free outcomes were seen in seven patients with epileptic spasms (64%) and four with partial seizures (36%). The multilobar epileptogenic zones existed in patients with epileptic spasms, compared with the focal epileptogenic zone in patients with partial seizures. There was no difference of MRI and histopathology findings in cortex and subcortical white matter between two groups.

High kurtosis of intracranial electroencephalogram as a marker of ictogenicity in pediatric epilepsy surgery

OBJECTIVE We determined whether kurtosis analysis of intracranial electroencephalogram (EEG) can estimate the localization of the epileptogenic zone. METHODS We analyzed 29 pediatric epilepsy patients who underwent intracranial EEG before focal resective surgery. We localized the brain regions with high kurtosis, the seizure onset zone (SOZ) and the regions with high-rate, high-amplitude and long-duration interictal paroxysms ≥20 Hz. We tested correlations between the surgical resection of those regions and post-surgical seizure outcome, and correlations between kurtosis and the rate/amplitude/duration of interictal paroxysms. RESULTS The resection of the regions with high kurtosis correlated with 1-year post-surgical seizure outcome (p=0.028) but not with 2-year outcome. Kurtosis showed more significant correlation with 1-year seizure outcome than the SOZ and the rate/amplitude/duration of interictal paroxysms. Kurtosis showed positive, independent correlations with the amplitude and duration of interictal paroxysms (p<0.0001) but not with the rate (p=0.4). CONCLUSIONS The regions with high kurtosis provide more reliable information to predict seizure outcome than the SOZ and the regions with high-rate/amplitude and long-duration interictal paroxysms. Kurtosis reflects combined effects of the amplitude and duration of the interictal paroxysms. SIGNIFICANCE High kurtosis suggests the regions with acquired ictogenicity within the irritative zone.

Novel PLA2G6 mutations associated with an exonic deletion due to non-allelic homologous recombination in a patient with infantile neuroaxonal dystrophy

Novel PLA2G6 mutations associated with p.Asp283Asn and a unique intragenic deletion of exons 4 and 5 due to non-allelic homologous recombination were identified in a Japanese female patient with typical infantile neuroaxonal dystrophy. The patient showed progressive tetraplegia beginning at 9 months. An electroencephalogram showed a diffuse increase in fast waves, and brain magnetic resonance imaging showed progressive brain atrophy and T2 hypointensity in the globus pallidus.

Spatial relationship between fast and slow components of ictal activities and interictal epileptiform discharges in epileptic spasms

OBJECTIVE We analyzed the spatial distribution and concordance of fast (>10Hz) and slow (<5Hz) electroencephalogram (EEG) components of ictal activities and interictal epileptiform discharges (IIED) recorded by intracranial video EEG (IVEEG) in children with epileptic spasms (ES). METHODS We studied eight children with ES, who underwent IVEEG before resective surgery for epilepsy. We quantified the root-mean-square (RMS) amplitude of the fast and slow components of ictal activities during ES and IIED. We compared the concordance between the spatial distributions of the fast and slow components of ES and IIED. RESULTS There was a larger concordance between the spatial distributions of the fast and slow components in IIED than in ES (p=0.0206 and 0.0401). CONCLUSIONS The spatial concordance between the fast and slow EEG components was significantly different between ES and IIED. SIGNIFICANCE The mechanisms underlying the generation of slow EEG components may differ between ES and IIED. The slow EEG components of ES might indicate an extensive epileptic network involving remote symptomatic zones for ES in either the cortical or subcortical areas. The high spatial concordance between the fast and slow components of IIED suggests the involvement of a local inhibitory process within the epileptic cortex.

Five pediatric cases of ictal fear with variable outcomes

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

Simultaneous measurement of monoamine metabolites and 5-methyltetrahydrofolate in the cerebrospinal fluid of children

BACKGROUND We describe a new method for simultaneous measurement of monoamine metabolites (3-O-methyldopa [3-OMD], 3-methoxy-4-hydroxyphenylethyleneglycol [MHPG], 5-hydroxyindoleacetic acid [5-HIAA], and homovanillic acid [HVA]) and 5-methyltetrahydrofolate (5-MTHF) and its use on cerebrospinal fluid (CSF) samples from pediatric patients. METHODS Monoamine metabolites and 5-MTHF were measured by high-performance liquid chromatography with fluorescence detection. CSF samples were prospectively collected from children according to a standardized collection protocol in which the first 1-ml fraction was used for analysis. RESULTS Monoamine metabolites and 5-MTHF were separated within 10min. They showed linearity from the limit of detection to 1024nmol/l. The limit of quantification of each metabolite was sufficiently low for the CSF sample assay. In 42 CSF samples after excluding cases with possibly altered neurotransmitter profiles, the concentrations of 3-OMD, MHPG, 5-HIAA, HVA, and 5-MTHF showed significant age dependence and their ranges were comparable with the reference values in the literature. The metabolite profiles of aromatic l-amino acid decarboxylase deficiency, Segawa disease, and folate receptor α defect by this method were compatible with those in the literature. CONCLUSIONS This method is a simple means of measuring CSF monoamine metabolites and 5-MTHF, and is especially useful for laboratories not equipped with electrochemical detectors.

Determination of CSF 5-methyltetrahydrofolate in children and its application for defects of folate transport and metabolism.

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

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 patients 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.

Detection of fast (40-150 Hz) oscillations from the ictal scalp EEG data of myoclonic seizures in pediatric patients

OBJECTIVE We explored fast (40-150 Hz) oscillations (FOs) from the ictal scalp electroencephalogram (EEG) data of myoclonic seizures in pediatric patients to obtain insight into the pathophysiological mechanisms involved in the generation of myoclonic seizures. SUBJECTS AND METHODS The participants were 21 children (11 boys, 10 girls; age ranging from 5 months to 17 years 2 months) with myoclonic seizures associated with generalized (poly)spike-wave bursts in the ictal EEG data. The patients had heterogeneous etiologies and epilepsy diagnoses. In the ictal data, we detected FOs that clearly showed oscillatory morphology in filtered EEG traces and an outstanding spectral blob in time-frequency analysis. RESULTS We identified FOs in 61 (88.4%) of all 69 myoclonic seizures. Every patient had at least one myoclonic seizure-associated FO. The observed FOs were embedded in the spike component of (poly)spike-wave discharges, and they had a focal distribution with frontal predominance. They ranged in frequency from 41.0 to 123.0 Hz and involved both the gamma and ripple bands, and their spectral peak frequencies were higher in the group of patients with a genetic background free of apparent fundamental brain pathology than in the group of other patients (p = 0.019). CONCLUSION FOs were found to represent at least part of the cortical pathophysiological process in the generation of myoclonic seizures that should involve the thalamocortical network system.