Inhibitory control mechanisms in linguistic and non-linguistic contexts in bilingual aphasia

Abstract

In this project we examine mechanisms of linguistic and non-linguistic control in bilingual patients with aphasia for evidence of domain general cognitive control or domain specific cognitive control on tasks of low complexity and high complexity. Participants include 13 bilingual adults with aphasia and 20 neurologically healthy bilingual adults who are matched on age, years of education and measures of language experience. All participants completed two linguistic control tasks and two non-linguistic control tasks. Results from healthy controls and patients with less severe language impairment revealed that mechanisms of control do not overlap (i.e., indicative of domain specific cognitive control) on low complexity tasks, but do overlap (i.e., indicative of domain general cognitive control) on high complexity tasks, suggesting that as task demands increase, control mechanisms engage. In contrast, for patients with more severe language deficits, results revealed that control mechanism do not overlap on low or high complexity tasks, suggesting that (a) as task demands increase, linguistic and non-linguistic control mechanisms do not engage, thus they function differently compared to healthy participants and less severely impaired patients, and (b) there is a possibility that because patients with severe language deficits have difficulty with accessing lexical representations, this language impairment may supersede their ability to engage in linguistic control.