PMEs are a genetic disorders which previously had a nosological confusion. The characteristics of PMEs are action or intentional myoclonus, ataxia and mental decline. There are considerable geographic and ethnic variability, DRPLA and PMErelated disorder, benign adult familial myoclonus epilepsy (BAFME), are relatively popular in Japan whereas they are extremely rare in the other countries. The major PME disorders such as Lafora disease, Neuronal Ceroid Lipofuscinosis, Sialidosis, Unverricht-Lundborg disease, Mitochondrial disease, DRPLA, and BAFME were described along with case reports. Special attention is given to the BAFME which are adult onset photosensitive epilepsy with various degree of action and postural myoclonus and ocasional GTCs and has a dominant hereditary pattern and benign course. Recent advances in genetic studies provided a new aspects of the basic mechanism of PMEs, and now DNA diagnosis became possible in many cases. The locus of BAFME was recently found in chromosome 8 q 23.3-24.1. Neurophysiological aspects of all of these PMEs and BAFME had a high amplitude somatosensory evoked potentials (SEPs) except for DRPLA where SEP and the auditory brainstem potential (ABP) were suppressed. The myoclonus of DRPLA, clinically indistinguishable from those of the other PMEs, may have different mechanism such as subcortical origin.

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We present an infant who had West syndrome two months after status epilepticus.One month after the status epilepticus, EEGs showed multifocal spikes. Two months after the status epilepticus, when he began to have epileptic spasms, hypsarrhythmia appeared. Cranial magnetic resonance imagings showed mild cerebral atrophy, pre dominantly in frontal lobes, and single photon-emission computed tomography showed low perfusion of bilateral frontal lobes. The spasms were controlled by vitamin B₆. Before occurrence of West syndrome, his psychomotor development was normal, but delay of verbal development became apparent after the cessation of epileptic spasms.

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This study investigates alteration of regional cerebral blood flow (rCBF) and identification of epileptic foci in interictal frontal lobe epilepsy (FLE) using statistical parametric mapping (SPM). Noninvasive rCBF measurements using ^99mTc-ECD SPECT were performed on 23 patients with frontal lobe epilepsy and 49 age-matched normal subjects. The FLE patients were divided into three groups, 3 patients with dorsolateral and frontocentral seizures, 2 patients with supplementary motor seizures, and 18 patients with frontobasal-cingulate seizures by Mihara's classification determined by clinical and EEG findings. The SPM analysis revealed rCBF abnormality in frontal lobes in 12 patients when compared rCBF data for each patient with those for normal subjects in accordance with Mihara's classification in 8. On the contrary, rCBF abnormality in frontal lobes was detected in 4 patients by visual inspection in accordance with the classification in only one. The rCBF significantly decreased in orbitofrontal regions, frontopolar regions, and anterior cingulate gyrus in the group with frontobasal-cingulate seizures as compared with age-matched normal subjects with confounding covariates of plasma concentrations of antiepileptic drugs. These results suggest that SPM analysis of brain perfusion SPECT gives us useful information about frontal lobe epilepsy even in the interictal phase.

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We report 2 patients who showed myoclonic or generalized tonic-clonic seizures while playing electronic screen games (ESGs). We examined the relationship between seizures and ESGs by investigating the clinical features and by performing electrophysiological examinations in these 2 patients. The precipitating factor in both cases was playing special category games. Another precipitating factors of one case was playing piano or pipe, and the other was playing Japanese chess (“shogi”). No photoparoxysmal responses were induced in either case by intermittent photic stimulation, but, paroxysmal discharges clearly increased while playing special category games. Although many reports have suggested that photo-sensitivity is the main precipitating factor for seizures induced by ESGs, the seizures in our two cases were not classified as photo-induced seizures but rather as “pure ESGs induced seizures” whitch may be related to the cognitive or motion components of the game playing.

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We presented a patient with frontal lobe epilepsy who had a circumscribed cortical lesion in the left medial frontal lobe and confirmed epileptogenic zone in its vicinity by magneto-encephalographic (MEG) findings.
The patient was a 17-year-old girl who had suffered from frequent epileptic tonic extension of extremities following bilateral peri-oral contractions since the age of 1 year and 2months. Her seizures occurred almost daily at the examination. On the interictal scalp EEG frequent spikes were seen dominantly on Fz and Cz, though spike and spike with slow wave seemed bilateral and synchronous. On ictal scalp EEG the increased interictal spikes just before seizure were suppressed at the seizure onset and after then bilateral diffuse spike rhythm was followed. We could not define the exact epileptogenic focus on EEG. However the calculated equivalent current dipoles (ECDs) of interictal spikes and the ictal spikes at the seizure onset on MEG were densely clustered near the circumscribed lesion which was found in the left medial frontal lobe on MRI. Consequently, we thought that there was epileptogenic zone in the vicinity of lesion. MEG findings may be helpful to find the epileptogenic focus in the medial side of brain, though it will have to wait for further study.

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