Benign epileptiform transients of sleep. Clarification of the small sharp spike controversy.

Electroencephalograms were performed on 120 normal subjects sleep deprived for 24 hours. Twenty-four percent of the volunteers exhibited one or more epileptiform transients during stages 1 or 2 of non-rapid eye movement sleep. These potentials usually appeared as monophasic or diphasic spikes unaccompanied by sharp waves or focal slowing. When abundant, they occurred sporadically and independently over both hemispheres but were best developed in the anteromesial temporal regions. A 20 percent incidence of similar spikes was found in 599 consecutively referred patients recorded under the same conditions. We conclude that these epileptiform transients of sleep, which have been called "small sharp spikes," are normal and are of no diagnostic value in the evaluation of patients with seizures.