Comparison of neuropsychological functioning in Alzheimer's disease and frontotemporal dementia

Neuropsychological changes distinguishing mild Alzheimer's disease (AD) from frontotemporal dementia (FTD) have been described, but empirical verification of differential cognitive characteristics is lacking. Archival neuropsychological data on 15 FTD patients, 16 AD patients, and 16 controls were compared. Controls outperformed both patient groups on measures of verbal and nonverbal memory, executive ability, and constructional skill, with AD patients showing more widespread memory decline. No differences were found between the 3 groups in confrontation naming, recognition memory, or basic attention. Patient groups differed only in nonverbal memory, with FTD patients performing significantly better than AD patients. However, patient groups also differed in pattern of performance across executive and memory domains. Specifically, AD patients exhibited significantly greater impairment on memory than executive tasks, whereas the opposite pattern characterized the FTD group. These findings suggest that examination of relative rankings of scores across cognitive domains, in addition to interpretation of individual neuropsychological scores, may be useful in differential diagnosis of FTD versus AD.