VISUOSPATIAL IMAGERY IN ALZHEIMER-DISEASE

The purpose of the present study was to investigate the imagery abilit y of 8 ''probable'' Alzheimer disease patients using a standard task s ensitive to the disruption of the imagery system. These patients were selected based on their good performance on a prerequisite clock-setti ng task, and with 8 matched control subjects were then required to com pare the angles made by the hands on clock faces using only imagined s timuli. There were no significant differences between patients and con trols in performance on the clock-imagery task. These data are consist ent with models of information processing which postulate the relation ships between visual imagery and a short-term memory store and include a central executive system for allocation of cognitive resources.