EEG spectral power and mean frequencies in early heroin abstinence

The purpose of the present study was to investigate cumulative heroin effects on brain functioning by studying relationships among electroencephalography (EEG) spectral power and mean frequencies and heroin abuse history. Eyes-closed resting EEG data were collected from the 19 monopolar electrode sites in 33 heroin abusers and 13 age-matched healthy volunteers. The mean age of the patients was 23.1+/-4.5 years, the duration of daily heroin abuse (DDHA) ranged from 4 to 44 months, the intravenous doses of heroin ranged from 0.04 to 1.00 g/day, the abstinence length ranged from 6 days to 4.5 months. General linear model (GLM) repeated measures procedure revealed a significant group effect on the distribution of the mean power spectrum between bands and mean frequencies in almost all analyzed derivations. Further analysis demonstrated that these intergroup differences were diversely related to at least three aspects of heroin-taking history. Frequency shifts in alpha2 range, most prominent in frontal and central derivations, were related to duration of daily heroin consumption. Slowing of alpha1 mean frequency, most prominent in central, temporal, and occipital derivations, was registered mainly in heroin addicts who abused high doses of the drug. Spectral power characteristics of brain electrical activities in our patient population were strongly predicted by abstinence length. The present results give grounds to suppose that chronic heroin-taking induces neuronal oscillation frequency changes, which may contribute to the development of antisocial trends and some semantic processes disturbances in these patients. Supplementary neurophysiological deficit is characteristic for heroin addicts who takes high doses of the drug, however, its relation to heroin abuse remains unclear. Pronounced desynchronization is observed in acute heroin withdrawal, and spectral power characteristics tend to normalize almost completely during several weeks of abstinence.