Inhibitory control and the production of disfluencies in speakers with Alzheimer’s Disease

This paper presents preliminary findings from a longitudinal study that investigates the ability of speakers diagnosed with Alzheimer's Disease (AD) to manage distractions and the same speakers’ production of hesitations in semi-spontaneous speech. Previous research has found that two kinds of hesitation: silent pauses and reformulations, are significantly influenced by inhibitory control in healthy second language learners. Silent pauses are also well-known linguistic markers of disease progression in people living with AD and may evidence a speaker’s production problems, whereas reformulations promote the joint discourse. Inhibitory control is therefore associated with disfluencies that are personal and social. It was hypothesised that first language speakers with a diagnosis of AD would make fewer reformulations and produce more silent pauses relative to healthy individuals. Data that included a Stroop task, a two-minute monologue, and a two- minute category fluency task were collected and analysed from 11 participants with AD and 13 healthy Controls. In AD participants, only the number of silent pauses correlated with the Stroop task, while reformulations correlated with the MoCA, and silent pause duration with the MoCA and category fluency task, suggesting that the effects of disease- related cognitive decline rather than competing information were responsible for the lack of fluency.