Background & methods: Preattentive auditory processing and sensory memory were investigated by means of mismatch negativity (MMN) in a sample of 22 middle-aged abstinent chronic alcoholics and 25 age-matched healthy controls. Stimuli were presented at two inter-stimulus intervals (ISIs, 0.75 sec and 2.0 sec) in separate blocks.
Results: No significant differences in amplitude or latency of MMN were found between alcoholic and control subjects in either of the two ISI conditions. However, when age was included as a factor in the analysis, MMN amplitude was attenuated in chronic alcoholics who were older than 40 years of age.
Conclusions: These results indicate that the automatic stimulus-change detector mechanism associated with MMN generation is impaired in chronic alcoholics over the age of 40, suggesting that the neurotoxic effects of chronic consumption of alcohol are more prone to appear after a critical age.