Relation between ocular manifestations and onset of spike-and-wave discharges in petit mal epilepsy.

Ocular manifestations are prominent in petit mal attacks. The nuclei innervating the extraocular muscles lie in mesencephalic and pontine regions of the brainstem which have been regarded by some as critical areas in the generation of petit mal attacks. Ocular signs and their timing relative to spike-and-wave onset were studied cinematographically in 4 patients with petit mal epilepsy. Each patient showed a consistent pattern of eye deviation or fixation during spike-wave bursts. Neither the activation of oculomotor pathways, as indicated by eye deviation, nor their inactivation, as suggested by interruption of ongoing elicited ocular activity, preceded the appearance of spikewaves. Because ocular manifestations began only after the onset of spike-wave, this study provided no evidence that brainstem oculomotor regions were involved in the initiation of these petit mal attacks.