Unconsciousness, automatisms, and myoclonic jerks with diffuse rhythmic 9-Hz discharges.

A 25-year-old man presented with seizures characterized by unconsciousness, automatic behavior, and myoclonic jerks lasting 0.5 to 8 sec. Videotape analysis of 300 simultaneously recorded electroencephalographic and clinical attacks revealed 8- to 9-Hz 150 to 200 muV sharp waves beginning in both medial temporal areas during eyelid flutters. When discharges spread diffusely on both sides and lasted 2 to 3 sec, 20 degrees forward flexion of the head, unconsciousness, pupil dilation, and staring became evident. Asymmetrical myoclonic jerks invariably appeared. When paroxysms were greater than 3 sec, automatisms and tonic posturing occurred. The electroencephalographic and clinical seizures appeared during the awake and relaxed states, i.e., with normal alpha rhythm. They were suppressed during physical and mental activities and during sleep, i.e., in the absence of alpha rhythm. Our studies suggest that these seizures associated with diffuse electroencephalographic alpha-like activities are subcortical in origin and should be tested in their responsivity to alpha suppressants and inducers.