A short neuropsychologic and cognitive evaluation of frontotemporal dementia

OBJECTIVE: To elaborate a brief but efficient neuropsychological assessment of frontotemporal dementia (FTD), selecting the most specific and sensitive cognitive and behavioural items for distinguish between AD and FTD in the earlier dementia stages.

METHODS: Retrospective study with three groups, 35 patients with FTD, 46 with AD and 36 normal subjects, were administered the MMSE, FAB, Tower of London and Stoop's test along with a 98 items behavioural and cognitive questionnaire. The most sensitive items were selected and validated internally for diagnosis by lineal discriminant analysis.

RESULTS: From the 98 items in the questionnaire, 29 showed significant discriminatory power. Non-cognitive symptoms with higher odd-ratio for FTD compared to AD were impairment in social behaviour (disinhibition, aggressiveness), loss of insight and inappropriate acts. Language disorders, such as echolalia, verbal apraxia or aggramatism, dominate in the cognitive profile of FTD. FAB was confirmed as the best cognitive instrument to differentiate FTD and AD. A linear discriminant function with the combination of the FAB score and the items from our questionnaire with higher OR for FTD accurately classified 97% of individuals.

CONCLUSIONS: The neuropsychological tests allow the differentiation between FTD and AD. The combination of FAB test with the assessment of key behavioural and cognitive symptoms appears helpful in this distinction.