Geographical remote memory and verbal fluency in Alzheimer's disease

Abstract

It has been previously shown that persons with Alzheimer's disease (AD) have impaired remote memory for geographical information. In particular, individuals with AD have greater difficulty locating specific (i.e., cities) vis‐à‐vis gross (i.e., states) geographical features on a map. Similarly, it has been found that individuals with AD are disproportionately impaired in producing specific exemplars relative to category labels on category (semantic) verbal fluency tasks. One intent of this study was to replicate the findings concerning remote spatial memory and to determine whether persons with AD also show disproportionate impairment in retrieving specific rather than more global information on geographical verbal fluency (cities and states) tasks. A 2nd purpose of the study was to examine the relation between geographical spatial memory and geographical verbal fluency tasks and to address whether a similar mechanism might underlie impaired performance on these tasks. Our findings indicated that, compared to an age and education matched control group, the AD group was disproportionately impaired in locating cities relative to states on the Fargo Map Test‐Revised (FMT‐R). Similarly, the AD group showed a more pronounced impairment on the city than state verbal fluency task. The control group's scores on the FMT‐R and geographical fluency tasks were not significantly correlated, whereas those of the AD group were correlated. This suggests that a similar mechanism (a retrieval deficit or bottom‐up breakdown of hierarchically organized spatial knowledge) might underlie the AD group's impairment in geographical knowledge.