Neuropsychological approach to epilepsy is indispensable to assess cognitive function in an interictal period, to disclose the semiology of non-convulsive status epilepticus, and to identify a seizure-precipitating factor. We have investigated the 3 rd point by loading systematic cognitive tasking, termed “neuropsychological EEG activation (NPA), ” during standard EEG recordings. NPA tasks consisted of reading, speaking, writing, written calculation, mental calculation, and spatial construction. The NPA tasks provoked epileptic discharges in 7.9% of the 480 epileptic patients and were often accompanied by myoclonic seizures. Seizure-precipitating mental activities were almost exclusively related to idiopathic generalized epilepsies (IGEs). Based on the results of various tasks, 2 forms of precipitating factors were identified: (1) action-programming activity, which is a higher mental activity associated with use ofthe hands (e. g., writing, written calculation, and block design test), and (2) thinking activity, which is a higher mental activity not requiring hand movements (e. g., making a sentence in mind, and mental rotation). These results surggest that NPA is a useful tool for examining the relationship between cognitive function and epileptic seizures, and that the IGE patients with myoclonic seizures are vulnerable to higher mental activity. We also discussed the classification of reflex epilepsy induced by higher mental activity.

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We conducted a follow-up study of 98 subjects who presented with seizures after watching a “Pocket Monster” TV animation (broadcast on December 16, 1998). We examined the relationship between the electroencephalographic (EEG) findings and the clinical symptoms after watching “Pocket Monster”. Thirty-five subjects with paroxysmal EEG waves in routine examination and with/without photoparoxysmal responses (PPRs) by intermittent photic stimulation were classified as the type I group, 18 subjects without paroxysmal EEG waves in routine examination and with PPRs were classified as the type II group, and 23 subjects with neither paroxysmal EEG waves in routine examination nor PPRs were classified as the type III group. In the type I group, 4 subjects showed photosensitive seizures and 7 subjects showed spontaneous seizures. In the type II group, 4 subjects showed photosensitive seizures and one subject showed spontaneous seizure. In the type III group, one sudject who had epileptic seizure in the past showed spontaneous seizures. In the subjects who showed seizures after watching “Pocket Monster”, the following characteristics were seen. (1) All subjects but one who showed photosensitive seizures belonged to the type I or type II group, and they were either not taking or had discontinued anti-epileptic medication when the photosensitive seizures occurred. (2) All subjects who showed spontaneous seizures for the first time after watching “Pocket Monster” belonged to the type I group.

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Occipital lobe epilepsy (OLE) is one of the symptomatic partial epilepsies (SPE), and is associated with ictal visual symptoms in general. However, it is very difficult to diagnose OLE, because (1) the boundaries of the occipital lobes are vague, (2) epileptic discharges originating from the occipital lobes spread into other lobes easily, (3) seizure manifestations of OLE are complex. We studied about 10 patients who had undergone simultaneous recording of EEG and magnetoencephalography (MEG), and whose dipoles localized in the occipital lobes. They were divided into three groups, the mesial type, the lateral type, and mixed type. We examined the relation between clinical symptoms and dipole localizations in these cases. Mesial type patients had elementary hallucinations such as phosphenes, and the lateral type had complex hallucinations. Visual hallucinations (elementary or complex) may be useful in inferring both localization and extent of epileptogenesis.

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Three patients (2 females, one male) with infantile spasms (IS) associated with partial seizures (PS) are reported. All cases had an unremarkable perinatal history and had shown normal development until seizure onset. Using prolonged video/EEG monitoring we confirmed PS intervened during the cluster of IS in two cases and that another patient developed IS several seconds later following PS. Interictal EEG showed hypsarrythmia in all. MRI revealed a focal cystic lesion in the left temporal lobe in one case and the other case showed hypoperfusion of the left temporal region on SPECT. In all patients IS responded initially to VPA with vitamin 136 or ACTH, but relapsed. Two patients responded ACTH again, while one medically refractory girl with an anatomical lesion on MRI underwent surgical resection with excellent outcome. Pathology of the resected lesion showed a cortical dysplasia. Her development was normal at onset (DQ 91 at age 10 months), but moderately retarded just before operation (DQ 49 at age 3 years). After operation she has been seizure-free for 25 months, but continues to exhibit some degree of developmental delay (DQ 53 at age 3 years 11 months). Surgical intervention might be considered early in the medically refractory cases with anatomical lesions.

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Ictal and interictal magnetoencephalography (MEG) and electroencephalography (EEG) were simultaneously recorded in a 9-year-old boy who had focal motor seizures of the right hand. Although ictal and interictal EEGs showed only rare epileptic activity, MEGs recorded extremely clear ictal spikes and interictal spike rhythms. Equivalent current dipoles (ECDs) calculated from the ictal and interictal MEG spikes located a spot about 1 cm anterior to the ECDs of the sensory evoked field of the right hand. From the concordance of these MEG findings with clinical symptomatology, frontal lobe epilepsy with the epileptic focus in the left primary motor area was diagnosed. This case proved that MEG is useful for the diagnosis of epilepsy especially in patients who showed weak EEG abnormality.

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