Processing of language switches in bilingual individuals with aphasia: An event-related potential comparison
Switching between languages, or code-switching, is a common phenomenon in bilingual individuals. In proficient bilinguals, these switches are done with ease and are used for many purposes. Contrary to popular belief, these switches are rule-governed and follow grammatical structure. Bilingual individuals diagnosed with aphasia present with difficulty processing languages and these language switches. With the increase in bilingual individuals, it is likely that the speech-language pathology community will see an increase of bilingual individuals with aphasia on their caseload. For this reason, the purpose of this study is to increase our understanding of the neural processes involved in processing of language switches and how grammatical structure plays a role in this population. Event related potentials (ERPs) were used to compare a group of five bilingual individuals with aphasia and eight individuals with no history of brain damage during an auditory task consisting of language switches under four different conditions. The participants were presented with a total of 80 sentences, each containing a language switch from either English (E) to Spanish (S), or Spanish to English. The language switches were made to either adhere to, or violate grammatical rules. N400 and P600 peak amplitude and latency were compared between the two groups for each type of switch. Cortical activation maps between the two groups were also compared. It was hypothesized that there would be no differences between the two groups during any of the switches. Though there were no statistically significant effects on peak amplitude and latency between the two groups and type of switch, based on the results of the grand averaged waveforms and cortical activation maps, the study found there were differences in the processing of the language switches associated with the groups and type of language. While both groups followed patterns reported by previous research, resulting in a large N400 during grammatical switches and large P600 during ungrammatical switches, the presence of these peaks does not indicate appropriate processing. Cortical activation highly differed between the two groups. Further research is therefore needed to expand on these results and test for comprehension of the language switches in bilingual individuals with aphasia.
Rodarte, Lizette, "Processing of language switches in bilingual individuals with aphasia: An event-related potential comparison" (2015). ETD Collection for University of Texas, El Paso. AAI1591987.