Walsh & Hoyt: Disturbances During Seizures

In 1881, Gowers noted that during the course of a generalized tonic-clonic seizure (grand mal seizure), there was brief bilateral pupillary miosis in the tonic phase of the seizure followed by bilateral pupillary dilation in the clonic phase. Other authors reported loss of the pupil light reflex as well during grand mal seizures. These pupil findings also occur regularly during generalized seizures without motor activity (i.e., petit mal or absence seizures). Jammes examined and photographed the pupillary size and reactivity in six patients during attacks of petit mal seizures. He found that bilateral pupillary dilation with loss of reactivity to light occurred consistently in all six patients during their absence attacks. Afterwards, when consciousness was regained, there was often mild pupillary miosis and facial flushing. The mechanism of the pupillary dilation that occurs during generalized seizure activity appears to be a combination of interruption of parasympathetic impulses and irritation of the sympathetic system. The postictal miosis probably represents decreased supranuclear inhibition to the parasympathetic midbrain nuclei.