EEG and Neurocognitive Changes in Chronic Methamphetamine Abuse

Methamphetamine is a potent and highly addictive psychostimulant that has become very popular on the illicit drug market. There is a large amount of literature regarding the neurocognitive changes associated with chronic methamphetamine exposure that are present in currently abstinent individuals. However, the evidence about the possible reversibility of such changes is less clear and only sparse data exists concerning the electroencephalographic (EEG) changes in methamphetamine users. We present a case of a 38 year old male with a 10 year history of continuous abuse of high doses of methamphetamine. The patient has been incapable of adequate social functioning for the last two years and during that period has also been repeatedly admitted to a psychiatric ward due to methamphetamine associated aggressive behavior. After 25 days of abstinence, neurocognitive testing revealed mild cognitive impairment that was most pronounced in psychomotor speed and sequencing in working memory. EEG assessment performed by both visual inspection and quantitative EEG brain mapping showed a slowing of the frequency of dominant occipital activity to the sub alpha frequency band as well as an increase of theta power. No pathological findings were seen on the Magnetic resonance imaging of the brain, however, repeated EEG 20 days later confirmed an abnormal slowing of the dominant alpha frequency. Our findings are in accordance with the limited data available in the literature. However, further studies are needed to confirm the utility of EEG as a marker of methamphetamine toxicity, as well as the association between EEG findings and the neurocognitive performance and the reversibility of both variables in the case of sustained abstinence.