EEG absolute power during extended cocaine abstinence.

We examined the effects of cocaine withdrawal on EEG during 3 months of abstinence. Twenty physically healthy cocaine users (80% men, 80% African American, mean (SD) age, 34.8 (4.1) years, 9 (5.4) years of cocaine use, minimal recent use of other drugs) were subject to 1 to 3 EEG recordings during 3 months of monitored abstinence on a closed clinical research ward. Three-minute eyes closed EEG recordings used 8 or 16 leads located at standard International 10/20 scalp sites. First EEG was recorded 16.8 (13.6) days after last cocaine use. Beta1 absolute power in the left temporal region and delta power in the mid right hemisphere (temporal region) increased significantly over time. Eight subjects tested during the first 2 weeks of abstinence showed trends toward decreased absolute power in all bands except beta1 in the left frontal region, and toward decreased absolute delta power in the mid right hemisphere, compared with 8 nondrug-using controls. These results are not totally consistent with some previous studies, which may be the result of differences in subject characteristics and EEG recording procedures. The findings suggest that chronic cocaine use is associated with EEG changes that may reflect persisting brain electrophysiological abnormalities during cocaine abstinence.