Disfluency patterns in Alzheimer’s disease and Frontotemporal lobar degeneration

Disfluencies may reflect various mechanisms: word finding difficulties, planning strategies, inter- individual cognitive variability, etc. In the current paper, we examined disfluency production in patients with behavioural variant of Frontotemporal lobar degeneration (bvFTLD), compared to patients with Alzheimer’s disease (AD) and healthy older adults. We showed that bvFTLD participants have lower speech rate and produce more incomplete utterances. However, those measures were not correlated with language abilities. On the contrary, AD participants did not differ from healthy controls on disfluency production, but discourse measures were correlated with participants’ lexical-semantic impairment. This provides evidence for different disfluency patterns in AD and FTLD, and a distinct role of disfluencies, depending on the population.