[Clinical-electrophysiological pattern of juvenile myoclonic epilepsy].

18 patients (9 females, 9 males) with juvenile myoclonic epilepsy (JME) were studied. Despite a fairly long duration of the disease (from 1 to 34 years--mean 9.5 years) the patients had not been properly diagnosed. In all cases routine serial EEG examinations, 24-hour EEG with Medilog System 9000, and polygraphic Video/EEG/EMG recording were done (Videometry Processor, Glonner). Typical attack triads occurred in 7 cases (39%), grand mal seizures and myoclonic attacks in 10 cases (56%), one patient had only myoclonic seizures. EEG demonstrated already in routine recording occurrence of seizure activity with spike/polyspike-slow wave 3-6 Hz complexes. 24-hour EEG made possible demonstration of these complexes in the remaining 4 cases. Seizure activity during clinical myoclonic seizures were recorded in 8 cases, and during absences in 2 cases. A valuable method was also Video/EEG/EMG recording which showed occurrence of both myoclonic seizures (in 5 cases) and absences (9 cases). Three patients with absences were not aware of their seizures. In 8 patients EEG findings demonstrated focal abnormalities which contributed to previous diagnostic errors. The described clinical and electrophysiological features met fully the diagnostic criteria of JME. In the Polish literature this is the first report on such a large groups of JME cases. Attention is called to diagnostic difficulties due to poor knowledge of this disease and its manifestations which leads to inaccurate history taking. Another cause is non-availability of full neurophysiological diagnostic facilities in many centers.