Decreased complexity of the EEG in patients with Methamphetamine dependence

Abstract

Neurobiological basis of the methamphetamine (MA) addiction is not well understood. The aim of this study was to estimate the Approximate Entropy (ApEn), an information- theoretic measure for irregularity, to investigate the complexity of the EEG in MA dependent patients and then to assess the relationship between cortical deterioration by MA and EEG abnormality. The EEG was recorded from 21 MAdependent patients and 21 age- and gender-matched healthy subjects in 16 scalp electrodes, and their ApEns were estimated from two groups. We found a decrease in ApEn vales in the MA-dependent patients at all electrodes (P<0.001), compared with those of normal controls, and the negative correlation between the ApEn values and the severity of MA-dose craving measures including the amount of dose, the period of intake etc, which cannot be detected by the conventional spectral analysis. This finding suggests that ApEn of the EEG is an efficient diagnostic tool for detecting the severity of cortical dysfunctions in MA-dependent patients.