RECOGNITION OF FAMILIAR AND UNFAMILIAR MELODIES IN NORMAL AGING AND ALZHEIMERS-DISEASE

We tested normal young and elderly adults and elderly Alzheimer's dise ase (AD) patients on recognition memory for tunes. In Experiment 1, AD patients and age-matched controls received a study list and an old/ne w recognition test of highly familiar, traditional tunes, followed by a study list and test of novel tunes. The controls performed better th an did the AD patients. The controls showed the ''mirror effect'' of i ncreased hits and reduced false alarms for traditional versus novel tu nes, whereas the patients false-alarmed as often to traditional tunes as to novel tunes. Experiment 2 compared young adults and healthy elde rly persons using a similar design. Performance was lower in the elder ly group, but both younger and older subjects showed the mirror effect . Experiment 3 produced confusion between preexperimental familiarity and intraexperimental familiarity by mixing traditional and novel tune s in the study lists and tests. Here, the subjects in both age groups resembled the patients of Experiment 1 in failing to show the mirror e ffect. Older subjects again performed more poorly, and they differed q ualitatively from younger subjects in setting stricter criteria for mo re nameable tunes. Distinguishing different sources of global familiar ity is a factor in tune recognition, and the data suggest that this ty pe of source monitoring is impaired in AD and involves different strat egies in younger and older adults.