Behavioral quantitation is more sensitive than cognitive testing in frontotemporal dementia

Abstract

Objective: To compare behavioral and cognitive testing in the clinical diagnosis of frontotemporal dementia (FTD).

Methods: A clinically defined cohort of FTD (n = 52) is compared with 52 Alzheimer disease (AD) patients on a Frontal Behavioral Inventory (FBI) and cognitive tests (e.g., Mini-Mental State Examination, Mattis Dementia Rating Scale, Western Aphasia Battery, Wechsler Intelligence Scale, Wechsler Memory Scale). Fourteen patients with FTD had autopsy confirmation, and their tests are also compared with the rest of the FTD population.

Results: The FTD and AD groups were matched in sex, duration, and severity of dementia. The total scores on the FBI showed the largest difference. Mini-Mental State Examination and Mattis Dementia Rating Scale total scores did not discriminate between the two groups. Memory subscores were lower in the AD group, and conceptualization and language-related scores were worse in the FTD group. Milder and earlier affected patients, who could carry on a large battery of neuropsychological tests, were much better distinguished by the FBI scores on discriminant function analysis. In contrast to 78% by the cognitive tests, 98% of the FTD and AD patients were differentiated by the FBI.

Conclusions: Although memory scores were lower in AD and language scores in the FTD population, many of the cognitive tests do not distinguish between FTD and AD. On the other hand, a behavioral inventory is a useful adjunct in the diagnosis of FTD. Postmortem validation was carried out in a sizeable subset of the population, showing similar behavioral and cognitive data.