Effects of chronic drinking on verb generation: an event related potential study

In alcohol dependent individuals, abnormalities in brain functioning have been revealed using event-related potential (ERP) methods. In the present study, we investigated whether in non-alcohol dependent drinkers functioning of the brain is also compromised as a function of recent and lifetime drinking history (LDH). An ERP verb generation task consisting of two conditions (generating verbs describing the use of visually presented nouns versus reading nouns aloud) was used; subtracting ERPs in the latter condition from those in the former should reveal the sequence of brain processes involved in verb generation. Four groups were included, consisting of individuals drinking either lightly, moderately, heavily, or excessively (overall mean age 46.6 years). Participants were sober at the time of testing. Although the excessive group had the highest per cent retrieval errors, there was no continuous relationship between this score and amount of alcohol consumption. However, number of glasses per week affected differential ERPs associated with verb generation both at short (120-220 ms, mid-frontal sites) and at longer latencies (from 700 ms on),left-temporal and right-frontal electrode sites (T7, F6). It is concluded that moderate, heavy, and excessive drinkers, compared to light drinkers, show abnormal brain potentials associated with verb generation over frontal and temporal areas. Moderate to excessive drinking alters some but not all brain processes involved in verb generation. In particular the frontal and temporal brain areas appear to be vulnerable for the effects of chronic lifetime drinking.