Differential aspects of sleep epilepsy.

A review of patients with epilepsy showed that 5.9% had seizures exclusively in sleep (ES) and 4.7% had seizures predominantly but not exclusively in sleep (PS). These groups were compared with a group (W) with seizures mainly in wakefulness. The following significant differences were obtained: 1) generalized convulsions predominated in the ES while partial seizures were more common among PS and W patients, 2) seizures occurred less frequently in the ES group, and 3) more W patients had EEGs with generalized epileptiform activity and positive family histories for epilepsy. We suggest the lower frequency of seizures in the ES group and the declining prevalence of sleep epilepsy are due to: 1) the high proportion of generalized as opposed to partial seizures in sleep and 2) more effective control of generalized seizures compared to partial seizures by modern anti-epileptic drug management.