THE SECONDARILY GENERALIZED TONIC-CLONIC SEIZURE - A VIDEOTAPE ANALYSIS

We studied 120 generalized tonic-clonic seizures (GTCSs) in 47 patient s with video-EEG telemetry. GTCSs were preceded by antecedent seizures , including 13 simple partial, 70 complex partial, 17 simple partial l eading to complex partial, seven tonic, seven clonic, and one typical absence. We divided GTCSs into the following phases: onset of generali zation, pretonic clonic, tonic, tremulousness, and clonic. The mean GT CS duration was 62 seconds. There was a nonsignificant trend toward lo nger duration on reduced antiepileptic drug doses. Marked heterogeneit y in GTCS phenomenology was present; only 27% of seizures included all five phases. Individual phase duration and clinical expression, inclu ding tonic and clonic phases, was highly variable. The clinical phenom ena suggest that multiple cortical and subcortical routes of spread ma y exist. When GTCSs last longer than 2 minutes, intravenous antiepilep tic drug treatment should be initiated.