Efficiency of attentional processes in bilingual speakers with aphasia

ABSTRACT

Background: Globalization has resulted in a growing bilingual population worldwide; thus, bilingual speakers with aphasia are also increasing. The ability to juggle languages has been reported to enhance attentional control abilities in healthy populations. However, few studies have looked at the impact of bilingualism on attentional control abilities in individuals with aphasia. Different subcomponents of attention are seldom studied in bilingual aphasia.

Aims: The goal of the study is to explore the influence of bilingualism on three subcomponents of attention in individuals with aphasia, namely alerting, orienting and executive control. The study aimed to examine whether (1) individuals with aphasia show evidence of an attentional deficit in comparison to language-matched healthy peers, (2) there is evidence of a bilingual advantage in attentional mechanisms, and (3) there is a relationship between bilingualism and subcomponents of attention.

Methods and Procedures: All the participants (10 French-English bilingual and 7 French monolingual adults with aphasia and 32 monolingual and bilingual healthy controls) performed a behavioural version of the Attention Network Test. The efficiency of the three attentional networks was assessed by measuring how response times varied with different warning cues and flanker type, resulting in alerting, orienting and executive control effects. Objective and subjective measures of bilingualism were also included.

Results: Results confirmed a bilingual advantage in attentional mechanisms with and without aphasia. More specifically, group difference for healthy controls was evident in the accuracy rate only. For individuals with aphasia, between-group comparisons revealed differences in alerting ability: the bilingual group presented a significantly greater difference score than the monolingual group in the mu (μ) component of the response time distribution, whereas the monolingual group was able to take advantage of the alerting cue in the tau (τ) component. Furthermore, the monolingual and bilingual speakers with aphasia exhibited reduced alerting and more interference effect when compared to their respective healthy controls.

Conclusions: This study provides evidence that bilingualism impacts attentional mechanisms in individuals with aphasia as well as healthy controls. Specifically, bilingual individuals with aphasia showed more efficient alerting skills than monolinguals with aphasia. Ex-Gaussian data analysis revealed effects that might otherwise be thought to be non-existent. Considering the growing bilingual population, an understanding of the behavioural signs and symptoms of attentional abilities in individuals with aphasia is necessary for both theoretical and clinical purposes.

KEYWORDS:

• Bilingual aphasia
• subcomponents of attention
• ex-Gaussian analysis

Acknowledgments

The authors would like to thank Catherine Dubé for her help with the data collection.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by a Canadian Institutes of Health Research grant (CIHR: MOP-327158). Tanya Dash is supported by the postdoctoral fellowship from FRSQ.