The Boston Naming Test identifies presymptomatic anomia in MAPT mutation carriers

Abstract

AbstractBackgroundPrior studies of prodromal genetic frontotemporal dementia (FTD) have identified impaired executive function and social cognition in C9orf72 and GRN mutation carriers but few cognitive deficits have been found in MAPT mutation carriers.MethodWe investigated performance on the Boston Naming Test (BNT) in the GENetic Frontotemporal dementia Initiative (GENFI) cohort of 499 mutation carriers and 248 mutation negative controls divided across three genetic groups: C9orf72, MAPT and GRN. Mutation carriers were further divided into 3 groups according to their global CDR plus NACC FTLD score: 0 (asymptomatic), 0.5 (prodromal) and 1+ (fully symptomatic). Mutation carrier groups were compared to each other and to mutation‐negative controls using a bootstrapped linear regression model, adjusting for age and education.ResultWe found that all of the symptomatic (1+) groups performed significantly worse on the BNT than controls, and worse than the prodromal and asymptomatic mutation carriers within the same genetic group. The MAPT symptomatic group also performed significantly worse than the GRN and C9orf72 symptomatic groups. Furthermore, both the MAPT asymptomatic and prodromal groups performed significantly worse than controls which was not the case in the other genetic groups.ConclusionThese results suggest a specific deficit in naming in MAPT mutation carriers consistent with previous literature, likely to be due to impaired semantic knowledge. Notably, this study shows that the BNT can be used to detect very early deficits in the disease course, allowing dissociation of MAPT mutation carriers from controls and from other genetic groups. Clinical trials focused on the prodromal period within individuals with MAPT mutations should use language tasks such as the BNT for patient stratification and as outcome measures.