The Impact of Aphasia on Working Memory in Bilingual Adults

The purpose of the current investigation was to explore the effects of aphasia on working memory (WM) in bilingual adults. Available research supports the notion that there are strong positive correlations between WM capacity and language function in monolingual adults with aphasia and that aphasic adults\u27 ability to comprehend language may be predicted by WM capacity. The relationship between WM capacity and auditory comprehension, as measured by the Token Test, was investigated in bilingual adults with and without aphasia. Additional areas of investigation included examination of the influence of aphasia on bilingualism and language proficiency as measured by differential performance in both languages on the Boston Naming Test (BNT); relationships between severity of aphasia, as measured by the Bilingual Aphasia Test (BAT); and WM, as measured by listening span. Sixteen participants between the ages of 26 and 91 were included in this study (mean age for women was 61.3; men was 52.8; 37% of the sample population was male, 63% was female). Eight participants were non-aphasic bilingual adults, the remaining 8 participants were bilingual aphasic adults. Results of the study indicated that both groups yielded relatively equivalent findings for the two languages on WM measures. Highly significant and strong positive correlations were observed between WM and auditory comprehension for both groups in both languages. There were no significant differences between English and Spanish results relative to auditory comprehension in the group with aphasia. There was, however, more variability on the BNT for the group with aphasia. Moreover, a significant difference between English and Spanish on the BNT was observed for the non-aphasic group. Significant relationships were found between language proficiency and aphasia severity for both languages; however, no significant differences were found between English and Spanish on the BAT. Nonetheless, moderate to strong positive linear relationships were observed between WM and aphasic severity (BAT) and strong positive relationships were found between language proficiency and aphasia severity for both languages for the group with aphasia. In conclusion, results suggest that the impact of bilingualism on WM for aphasic adults may be similar to what has been observed for monolingual aphasic individuals. Further research is needed relative to the nature of WM in bilingual adults with aphasia