A distinctive rhythmic EEG discharge of adults.

An unusual transient electroencephalographic pattern consisting of repetitive sharp-contoured wave forms in the range of 4--7 c/sec was seen in recordings from 65 patients who were between 42 and 80 years of age. This pattern was usually predominant over the parietal and temporal regions. No clinical alteration was associated with the pattern. Although the pattern resembled a subclinical EEG seizure discharge, it did not correlate with clinical seizures. The pattern occurred in patients with diverse clinical complaints, and although its mechanism of origin remains uncertain, it appears to represent a benign EEG phenomenon that has little diagnostic significance.