Association between quantitative EEG and neurocognition in methamphetamine-dependent volunteers

Objective: Exposure to methamphetamine is associated with long-lasting reductions in markers for dopaminergic neurons in preclinical models and in humans. These changes may be associated with alterations in brain electrical activity and in cognition. Methods: The sample included 9 methamphetamine-dependent subjects and 10 non-drug-using volunteers. Methamphetamine-dependent subjects were hospitalized for 4 days to document abstinence; non-drug-using volunteers were studied as outpatients. EEGs were recorded in the eyes-closed resting state, and absolute EEG power in each frequency band (0.5-4 Hz, 4-8 Hz, 8-12 Hz, and 12-20 Hz) was measured using a fast Fourier transform. EEG power was log-transformed prior to analysis. Cognition was measured using computerized reaction time tasks. Results: Within the methamphetamine-dependent group only, increased theta quantitative EEG (QEEG) power correlated significantly with reaction time on tasks that were more difficult or that were degraded by fatigue. Increased theta QEEG power also correlated with reduced accuracy on a working memory task. Conclusions: Increased QEEG power in the theta band is associated with worse performance on reaction time tasks in the methamphetamine-dependent sample but not in the non-drug-using volunteers. Significance: Methamphetamine dependence is associated with pathological alterations in brain electrical activity and in cognitive performance. QEEG appears to provide a sensitive measure of methamphetamine-associated alterations in brain function. (C) 2004 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.