Nonmatching- (oddity) and delayed nonmatching-to-sample performance in aging, alcoholic, and alcoholic Korsakoff individuals

Abstract

Measures of visual processing time, selective attention, and memory were obtained in 59 normal and alcoholic research participants (including 13 with alcoholic Korsakoff’s syndrome) ranging in age from 35 to 71 years. Performance was measured within the context of nonmatching-to-sample and delayed nonmatching-to-sample tasks. The tasks required the participants to identify the “odd” stimulus in a three-stimulus array (i.e., to choose one of two laterally located visual stimuli that did not appear as a central sample display). The sample stimulus varied in complexity, containing one or two stimulus dimensions (color and/or line tilt), and exposure duration of the sample stimulus varied from 20 to 500 msec. The interval between sample offset and response opportunity also was varied, from 0 to 30 sec. The results indicated that for all groups, simple (unidimensional) sample stimuli were easier than compounds (two dimensions), as were stimuli that were available for long durations and with short interstimulus delays. Duration of the sample’s exposure and the delay between sample and response choice were the variables that best differentiated among the groups. With short sample durations and at long delay intervals, the Korsakoff patients were the least accurate. Although older participants—regardless of their drinking history—also were impaired, the age-group differences were exaggerated in the alcoholics. The results emphasize the importance of processing deficits in amnesia of alcohol-related etiology, and in the cognitive decline that may accompany aging and alcoholism.