OCCASIONAL, inconspicuous, single spikes appear not uncommonly in electroencephalographic (EEG) recordings of drowsiness and light sleep. Gibbs and Gibbs found them in 6% to 8% of normal adults and in 1,025 cases from 38,082 consecutive laboratory referrals. They used the term "small sharp spikes" to designate these fast transients, which did not seem to have much pathologic significance in their experience.^1,2 Recently more interest has been expressed in these EEG signals with accounts of their electroclinical characteristics which differ in some respects from the Gibbs' observations.^3,4 Moreover, semantic and scientific objections have been raised to the appellation of "small sharp spikes."

The present study was prompted by relatively frequent observations of these EEG patterns in certain subgroups within a psychiatric population. The newly controversial nature of this subject provided additional impetus for investigation! The EEG and clinical findings from evaluations of subjects