Performance on a picture-word verification task by bilingual persons with aphasia

Given the estimated annual growth of bilingual aphasia cases (Lorenzen & Murray, 2008), there is an immediate need for research targeting the management of this population. There is reason to believe that the effective management of bilingual aphasia will not mirror approaches used for monolingual cases (Lorenzen & Murray, 2008). This investigation seeks to identify differences in language processing when utilizing first and second languages individually or in combination. A picture-word verification task was used, and it was hypothesized that providing persons with aphasia with additional written information to facilitate semantic processing would be beneficial, resulting in faster and more accurate response selection. Using a single subject design, three participants with aphasia, bilingual prior to onset, were administered the Bilingual Aphasia Test (BAT) and a picture-word verification task. Each of the participants presented with unique language histories and fluency levels of non-English languages. The experiment included two picture-word verification tasks incorporating the use of each language individually and both languages together. The fundamental design of the two paradigms was identical, but the stimuli utilized and the presentation sequence of the four conditions was different. In both paradigms, the four conditions were presented 30 times each, half as a picture-word match and half as a non-match. This resulted in a total of 240 stimulus presentations, 60 of each condition. Analyses were conducted on proportion correct (PC) and response time from stimulus onset (RT) within each of the four experimental conditions for each participant. Non-responses were removed from PC and RT data, and outliers were retained. Nonparametric statistics were used to identify significant associations in the case of PC and significant differences in the case of RT for each participant. For PC data, chi-square analyses were conducted to identify correlations between the number of accurate responses given in each condition. For RT data, the Kruskal-Wallis tests on rank scores (Kruskal & Wallis, 1952) were conducted for all participants. Mann-Whitney U tests were conducted on all possible contrasts when applicable. Post-hoc pairwise comparisons were made separately when applicable. All statistic tests were based on a significance level of a = . 05. Only one of the participants (P1) demonstrated a statistically significant difference between conditions. Although the other participants did not reveal statistically significant differences in performance, general trends were still observed suggesting better performance on one condition versus the others. The uniqueness and varied responses of the participants highlight the importance of considering the strengths and needs of each language when working with bilingual persons with aphasia. This would likely result in the greatest therapeutic gains as illustrated by Ansaldo and Saidi (2010), and may also reveal residual language abilities that can aid functional communication. The present investigation provides support for continued efforts on the topic of bilingual aphasia management and specifically speaks to the augmentation of input options aspect of design theory of alternative and augmentative communication (AAC) devices. Functional implications to indirectly target non-English languages and non-therapeutic opportunities to utilize these languages should also be considered to improve quality of life.