Executive Function Measures as Diagnostic tool in the Symptomatic, Prodromal and Presymptomatic phase of genetic Frontotemporal Dementia (FTD)

Abstract

Background and Objectives Executive functioning (EF) is a crucial cognitive domain in Frontotemporal Dementia (FTD) but sensitive neuropsychological measures are lacking. We aimed to examine whether the Brixton Spatial Anticipation Task (BSAT) and Hayling Sentence Completion Task (HSCT) are able to discriminate between clinical stages of genetic bvFTD. Methods The BSAT and HSCT were administered to 7 symptomatic gene mutation carriers and 4 sporadic bvFTD patients, 11 prodromal gene mutation carriers and 1 prodromal sporadic bvFTD patient, 53 presymptomatic gene mutation carriers and 51 controls. Mutation carriers, (25 GRN, 36 C9orf72, 7 MAPT, 2 TARDBP), were stratified by CDR® plus NACC FTLD score (0, 0.5, ≥1). Group differences in total score, errors and completion time were analyzed using Quade’s ANCOVA’s with age, sex and education level as covariates. Gene-specific differences and correlations with other neuropsychological tests were explored. Results Differences were found between CDR® plus NACC FTLD groups on completion time in part A of the HSCT, but could not be specified due to multiple testing corrections. No statistical differences were found in BSAT scores between CDR® plus NACC FTLD groups. Furthermore, C9orf72 mutation carriers performed worse than GRN mutation carriers on the BSAT and were slower in part A of the HSCT than controls. Discussion Differences in BSAT and HSCT performance were demonstrated between clinical stages of genetic bvFTD and between genetic mutations. The results provide insight in the prodromal phase of bvFTD but stress the need for further research on the BSAT and HSCT as potential diagnostic tools in early bvFTD.