The relationship between language control and cognitive control in bilingual aphasia

Abstract

This study examines language control deficits in bilingual aphasia in terms of domain specific cognitive control and domain general cognitive control. Thirty Spanish-English controls and ten Spanish-English adults with aphasia completed the flanker task and a word-pair relatedness judgment task. All participants exhibited congruency effects on the flanker task. On the linguistic task, controls did not show the congruency effect on the first level analysis. However, conflict ratios revealed that the control group exhibited significant effects of language control. Additionally, individual patient analysis revealed overall positive and negative effects of language control impairment and a benefit from semantically related word-pairs. Patient data suggest a dissociation between the mechanisms of language control and cognitive control, thus providing evidence for domain specific cognitive control. The influence of language proficiency on speed of translation was also examined. Generally, controls were faster when translating into their dominant language, whereas the patients did not show the same trends.

The nature of facilitation and interference in the multilingual language system: insights from treatment in a case of trilingual aphasia

“…In addition, she exhibited poor performance on the nonlinguistic flanker task when compared to controls. Her inability to perform this task is in contrast to other findings that individuals with aphasia can show high accuracy on the task and a congruency effect (i.e., faster reaction times for congruent than for incongruent conditions; Gray & Kiran, 2015). Therefore, the results observed in the participant reported here suggest deficits in interference suppression and nonlinguistic control in addition to language deficits.…”

“…Interestingly, the participant's overall reaction times improved over time, F(2, 57) = 20.94, p < .0001; the interaction between treatment and condition was not significant, F(2, 57) = 0.64, p = .52, and after treatment she still showed at-chance performance on congruent and incongruent trials. The participant's performance on congruent and incongruent trials was compared to data from 30 normal controls (Gray & Kiran, 2015) using Crawford and Garthwaithe's (2007) test. In addition to a p-value, this test also provides a point estimate of the percentage of the population that would obtain a more extreme score (i.e., lower on measures of accuracy; higher on reaction time, RT) than our participant, and these values are included below.…”

Neural basis of bilingual language control

“…This result led the authors to conclude that the two types of inhibitory control are dissociable, as proposed by Green et al . In line with this conclusion, Gray and Kiran found that aphasic patients with semantic deficits did not necessarily show EC deficits (for more evidence of dissociation between control domains, see Refs. and ).…”

“…Most of the available studies to date have investigated the role of EC in language comprehension by using lexical decision or semantic priming tasks, and only a few cases have been studied in the domain of word production . Moreover, almost all studies have compared linguistic performance to nonlinguistic inhibition using a flanker task or inhibitory control using verbal material …”

The effect of task complexity on linguistic and non-linguistic control mechanisms in bilingual aphasia

“…To examine the magnitude of conflict, we use the conflict ratio proposed by Green et al (2010): (incongruent -congruent)/congruent. Based on the literature (Gray & Kiran, 2016;Green et al, 2010), we hypothesize that NHBA will show an association between linguistic and non-linguistic conflict ratios for each level of complexity, suggesting that the ability to inhibit incongruent conditions on the linguistic task is related to the ability to inhibit incongruent conditions on the non-linguistic task, further providing evidence for domain general cognitive control. We expect that BAA conflict ratios will also show an association between linguistic and non-linguistic tasks.…”