Objective: To identify the cognitive tests that best discriminate between Alzheimer’s disease (AD) and frontotemporal dementia (FTD).
Methods: A comprehensive search of all studies examining the cognitive performance of persons diagnosed with AD and FTD, published between 1980 and 2006, was conducted. Ninety-four studies were identified, comprising 2,936 AD participants and 1,748 FTD participants. Weighted Cohen’s d effect sizes, percentage overlap statistics, confidence intervals, and fail-safe Ns were calculated for each cognitive test that was used by two or more studies.
Results: The most discriminating cognitive tests were measures of orientation, memory, language, visuo-motor function, and general cognitive ability. Specifically, these tests were: the ACE orientation and memory subtests, AVLT (recognition and delayed recall scores), Rey Complex Figure (delayed recall score), Recognition Memory Test (word version), WMS Logical Memory subtest (% retention, delayed recall scores), WMS Visual Reproduction subtest (delayed recall score), Selective Reminding Test (total recall), Graded Naming Test, Word-picture matching, WAB Spontaneous Speech subtest (fluency), Pyramids and Palm Trees test (word and picture scores), picture naming tasks, WAB Comprehension subtest, the Beery Developmental Test of Visual Motor Integration, and the MMSE. Although there were large and significant differences between groups on these measures, there was substantial overlap in the scores of the AD and FTD groups. Age, education, years since diagnosis and diagnostic criteria did not significantly contribute to the group differences.
Conclusions: Given the large overlap in the test performance of persons diagnosed with AD and FTD, cognitive tests should be used cautiously and in conjunction with a medical history, behavioural observations, imaging, and information from relatives when making differential diagnoses.
- Alzheimers disease
- cognitive assessment
- frontotemporal dementia
- neuropsychological deficits