Working memory for nonverbal auditory information in dementia of the Alzheimer type

Previous studies have revealed working memory impairments in individuals with dementia of the Alzheimer type (DAT) using visually and auditorily presented verbal materials, and visually presented nonverbal materials. Based on findings from behavioral and neuropathological studies, impairments in working memory for auditorily presented nonverbal materials have been hypothesized as well. Results of a study conducted by Kurylo, Corkin, Allard, Zatorre, and Growden (1993), however, failed to support this hypothesis. In the current investigation, perception and working memory for nonverbal auditory information (tones) were assessed using same-different discrimination tasks. Participants included individuals with no dementia, very mild DAT, and mild DAT. Unlike the findings from the study conducted by Kurylo and colleagues, our results suggest intact tone perception but a progressive decline in working memory for auditory nonverbal information with advancing DAT. A similar decline was also noted on a task assessing working memory for auditorily presented verbal information.