Implicit and explicit measures of memory for perceptual information in young adults, healthy older adults, and patients with Alzheimer's disease.

In this study, we examined how implicit and explicit memory for perceptual information (modality and voice) and lexical information varied across three subject groups: healthy young adults, healthy older adults, and age-matched older adults with dementia of the Alzheimer's type (DAT). These groups exhibited cross-modality (abstract) priming of the same magnitude. However, young adults produced greater modality- and voice-specific priming than the other two groups, whose performance was equivalent, suggesting that aging, but not DAT, reduced form-specific priming. Young adults demonstrated better recognition memory than healthy older adults, who in turn exhibited better recognition memory than older adults with DAT. In young adults, recognition memory was also sensitive to perceptual information. These findings indicate that aging can affect implicit memory for perceptual information, whereas DAT magnifies the effect of aging on explicit memory.