Different diagnostic definitions have been proposed for use in the characterization of mild cognitive disorders associated with aging. We have conducted a follow-up study of Age-Associated Memory Impairment (AAMI) subjects to better characterize AAMI and its natural clinical course. In our 3.6-year follow-up period, 9.1 % of the AAMI subjects developed dementia (Hanninen et al 1995). In this study, we approached AAMI from functional aspects by using electrophysiological methods.We recorded auditory and visual event-related potentials in 43 subjects fulfilling the National Institute of Mental Health criteria of AAMI (Crook et al 1986) and in 46 healthy age-matched controls. We found enhanced amplitudes and shortened latencies in multimodal ERPs as well as clearly impaired habituation of auditory N100 in non-attended conditions. Since habituation reflects automatic focusing of attention to relevant features of stimuli, impairment of this mechanism and subsequent defective memory trace formation may contribute to observed deficits in memory tests in AAMI.These findings suggest that Age-Associated Memory Impairment could be Age-Associated Attentional Impairment or that involuntary attention deficit could at least partly explain memory impairment in AAMI subjects.