Syntactic priming in bilingual patients with parallel and differential aphasia

Abstract

Background: Syntactic priming is the phenomenon by which the production or processing of a sentence is facilitated when that sentence is preceded by a sentence with a similar syntactic structure. Previous research has shown that this phenomenon also occurs across languages, i.e., hearing a sentence in one language can facilitate the production of a sentence with the same structure in another language. This suggests that syntactic representations are shared across languages.

Aims: The aim of the current study is to investigate this cross-lingual syntactic priming in patients with bilingual aphasia. To address this aim, we asked the following three research questions: (1) do patients with bilingual aphasia show priming effects within and across languages? (2) do these priming effects differ from the priming effects observed in control participants? and (3) does the pattern of priming effects interact with the type of aphasia?

Methods & Procedures: We tested two groups of patients: one group had similar impairments in both languages (parallel aphasia); in the other group, the impairments were larger in one of the languages (differential aphasia). We investigated syntactic priming within and across languages by means of a dialogue experiment.

Outcomes & results: We found significant cross-lingual priming effects in both patient groups as well as in a control group. In addition, the effect size of both patient groups was similar to that of the control group.

Conclusions: These findings support models that incorporate shared syntactic representations across languages, and are in favour of a non-localised account of differential aphasia in bilingual aphasia.

Keywords:

• Bilingualism
• Aphasia
• Syntactic priming
• Differential aphasia
• Parallel aphasia

Notes

¹ Caveat. With “type of aphasia” we do not refer here to the classical distinction between Broca and Wernicke aphasia, but rather to the distinction between parallel and differential aphasia.

² This questionnaire was filled out based on both the answers of the patients and their closest family member(s), present in the hospital on the day of testing.

³ This was not formally assessed, however the participants quickly understood the importance of firstlooking to the pictures, and then to the words. By only looking at the words, probability for erroneous sentences was high, because both nouns could act as an agent or a patient.

⁴ All experiment runs were taped and listened to for a second time in case of uncertainty.

⁵ Analyses with agent and patient agency as an additional factor yielded similar results with respect to the crucial findings described below. Because of the design complexity, the factor is therefore not included in the analyses in the main text.

⁶ We first selected a structure for the random effects to then add the fixed effects. Finally, the model was reduced by removing non-significant fixed effects and the model diagnostics were assessed.

⁷ We opted not to speculate about differences in the size of the effects, because of the differences in group size, which make it difficult to compare the size and the strength of the priming effects between the patient groups and the control group.

⁸ It may also be the case that the current study did not have adequate power to detect significant differences. It would definitely be interesting to replicate these findings in larger groups of participants.

⁹ These percentages reflect average priming effects of patients with parallel aphasia and control subjects across language conditions.