Auditory sensory memory as indicated by mismatch negativity in chronic alcoholism

Abstract

Objectives: A pre-conscious auditory sensory (echoic) memory of about 10 s duration can be studied with the event-related brain potential mismatch negativity (MMN). Previous work indicates that this memory is preserved in abstinent chronic alcoholics for a duration of up to 2 s. The authors' aim was to determine the integrity of auditory sensory memory as indexed by MMN in chronic alcoholism, when this memory has to be functionally active for a longer period of time. Methods: The presence of MMN for stimuli that differ in duration was tested at memory probe intervals (MPIs) of 0.4 and 5.0 s in 17 abstinent chronic alcoholic patients and in 17 healthy age-matched control subjects. Results: MMN was similar in alcoholics and controls when the MPI was 0.4 s, whereas MMN could not be observed in the patients when the MPI was increased to 5.0 s. Conclusions: These results provide evidence of an impairment of auditory sensory memory in abstinent chronic alcoholics, whereas the automatic stimulus-change detector mechanism, involved in MMN generation, is preserved.