The long-term course of seizure susceptibility in two patients with juvenile myoclonic epilepsy.

We have observed epileptic seizures of juvenile myoclonic epilepsy (JME) to be surprisingly sensitive to higher mental activity. The purpose of the present study was to examine changes over time in seizure susceptibility in two patients with JME who we followed-up for over 20 years. During the period, they were repeatedly subjected to provocative cognitive tasking, that is, to 'neuropsychological EEG activation'. Tasks included reading, speaking, writing, written arithmetic, mental calculation, and spatial construction. During the first 15 years after the onset of symptoms, higher mental activities, mainly associated with use of the hands, i.e. writing, written calculation, and spatial construction, as well as physiological factors, such as sleep deprivation, awakening, and fatigue, precipitated the seizures. Generalized tonic-clonic and absence seizures but not myoclonic seizures disappeared almost completely after antiepileptic treatment. After age 30, the provocative effect of higher mental activities persisted, and the myoclonic seizures decreased under same drug regimen. These observations suggest that the pathophysiology of JME improves with time but persists for a long time, and that it is closely related to a neural network involved in higher mental activities mainly associated with use of the hands rather than in physiological factors emphasized in prior reports.