ELECTROENCEPHALOGRAPHIC COHERENCE IN ACQUIRED-IMMUNE-DEFICIENCY-SYNDROME

We studied a quantitative electroencephalographic (EEG) measure, coher ence, in 28 patients with acquired immune deficiency syndrome (AIDS) a nd 56 uninfected volunteers. Compared with uninfected subjects, AIDS p atients had increased coherence in the 6- to 10-Hz band. The largest i ncreases in coherence were between frontal and occipital regions and b etween temporal and frontal regions. Coherence within contiguous regio ns was less affected. Eight of the 28 AIDS patients (29%) had clinical ly abnormal EEG findings, compared with four of the 56 uninfected cont rol subjects (7%). Among the AIDS patients, 12 had normal neuropsychol ogical performance, nine had mild impairment, and six had moderate imp airment. Coherence was increased in each subgroup of AIDS patients, in cluding those with normal neuropsychologic performance and/ or normal clinical EEG results. AIDS patients were then classified by quantitati ve EEG power in frontal head regions as ''abnormal'' (the upper third of patients) or ''normal'' (the remainder). Increased coherence was fo und among both groups. Because the development of abnormal neuropsycho logical performance or a clinically abnormal EEG examination indicates relatively advanced central nervous system disease, alterations in sp ecific coherence measures may detect subclinical effects of the human immunodeficiency virus on brain function before other changes are evid ent.