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Language impairment in the genetic forms of behavioural variant frontotemporal dementia.

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MacDougall, Amy M 
Bouzigues, Arabella 
Bocchetta, Martina 
Cash, David M 


BACKGROUND: Behavioural variant fronto-temporal dementia (bvFTD) is characterised by a progressive change in personality in association with atrophy of the frontal and temporal lobes. Whilst language impairment has been described in people with bvFTD, little is currently known about the extent or type of linguistic difficulties that occur, particularly in the genetic forms. METHODS: Participants with genetic bvFTD along with healthy controls were recruited from the international multicentre Genetic FTD Initiative (GENFI). Linguistic symptoms were assessed using items from the Progressive Aphasia Severity Scale (PASS). Additionally, participants undertook the Boston Naming Test (BNT), modified Camel and Cactus Test (mCCT) and a category fluency test. Participants underwent a 3T volumetric T1-weighted MRI, with language network regional brain volumes measured and compared between the genetic groups and controls. RESULTS: 76% of the genetic bvFTD cohort had impairment in at least one language symptom: 83% C9orf72, 80% MAPT and 56% GRN mutation carriers. All three genetic groups had significantly impaired functional communication, decreased fluency, and impaired sentence comprehension. C9orf72 mutation carriers also had significantly impaired articulation and word retrieval as well as dysgraphia whilst the MAPT mutation group also had impaired word retrieval and single word comprehension. All three groups had difficulties with naming, semantic knowledge and verbal fluency. Atrophy in key left perisylvian language regions differed between the groups, with generalised involvement in the C9orf72 group and more focal temporal and insula involvement in the other groups. Correlates of language symptoms and test scores also differed between the groups. CONCLUSIONS: Language deficits exist in a substantial proportion of people with familial bvFTD across all three genetic groups. Significant atrophy is seen in the dominant perisylvian language areas and correlates with language impairments within each of the genetic groups. Improved understanding of the language phenotype in the main genetic bvFTD subtypes will be helpful in future studies, particularly in clinical trials where accurate stratification and monitoring of disease progression is required.



Funder: Lemaire Family Foundation

Funder: Swedish Frontotemporal Dementia Initiative Schorling Foundation

Funder: Swedish Alzheimer Foundation

Funder: Karolinska Institutet; doi:

Funder: Weston Brain Institute; doi:

Funder: Miriam Marks Brain Research UK


C9orf72, Frontotemporal dementia, Genetics, Language, Progranulin, Tau, Humans, Frontotemporal Dementia, C9orf72 Protein, Magnetic Resonance Imaging, Atrophy, Language Development Disorders, tau Proteins, Mutation

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J Neurol

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Springer Science and Business Media LLC
Wellcome Trust (103838/Z/14/Z)
National Institute for Health and Care Research (IS-BRC-1215-20014)
Medical Research Council (MC_UU_00005/12)
MRC (unknown)
Cambridge University Hospitals NHS Foundation Trust (CUH) (146281)
Medical Research Council (MR/M008983/1)
Medical Research Council (MR/P01271X/1)
Medical Research Council (MC_U105597119)
MRC (MC_UU_00030/14)