Early recovery profiles of language and executive functions after left hemisphere stroke in bilingualism

Background: The nature, rate and pattern of recovery in bilingual persons with aphasia has been investigated over many years but several controversies remain. Recent evidence suggests that the relationship between executive function (EF) processes and language recovery may be distinct in bilinguals. An improved understanding of such underlying linguistic and cognitive processes may enhance assessment and treatment particularly in the acute phase. There is limited knowledge regarding how these processes interact and there remains little guidance as to the choice of an appropriate assessment battery. There is a need to develop a simple, effective battery which is sensitive to recovery processes, and in a multicultural and multilingual context, is able to distinguish normal from pathological profiles. Aims: The research study aimed to identify an assessment battery for language and EF that is sensitive to the recovery process for South African bilingual persons with aphasia at two time periods within the first 12 weeks post stroke. Methods and Procedures: A longitudinal comparison study was conducted at two acute rehabilitation centres. A sample of 10, second language English-speaking participants with aphasia (PWA) were assessed at two time periods within the first 12 weeks post stroke using the Comprehensive Aphasia Test (CAT) and a non-verbal EF battery. A matched control group of 19 neurologically intact bilingual, second language English speakers was assessed on the same battery on two occasions. Outcomes and Results: A between-group analysis identified statistically significant differences between the bilingual aphasic and control groups for language assessment as well as on the EF assessment (measuring updating, inhibition and shifting). The battery of tests also distinguished testing period and was appropriate for a variety of cultural groups. Distinctive profiles emerged across time for both language and EF subtests for the PWA. Conclusion: The combined battery appeared appropriate for the context and the results confirmed prior research suggesting that executive functioning may offer some explanations for differential recovery profiles. Exploring this distinct clinical profile may strengthen the decision-making process with regard to the type and language medium of therapy. Persistent EF deficits suggest the need for a cautionary interpretation of a bilingual advantage in the acute stage. Effective management in the acute phase of aphasia should be based on an understanding of recovery patterns, what is driving that pattern, and which cognitive deficits are contributing to the language behaviour. Delineating separate EFs and their linguistic correlates in bilinguals may aid management choices.