Structural priming from production to comprehension in aphasia.

Background: Many people with aphasia (PWA) show deficits in sentence production and comprehension, in part, due to an inefficient mapping between messages and syntactic structures. Structural priming-the tendency to repeat previously encountered sentence structures-has been shown to support implicit syntactic learning within and across production and comprehension modalities in healthy adults. Structural priming is also effective in facilitating sentence production and comprehension in PWA. However, less is known about whether priming in one modality changes PWA's performance in the other modality, crucial evidence needed for applying structural priming as a cost-effective intervention strategy for PWA. Aims: This study examined (a) whether production to comprehension cross-modality priming is effective in PWA, (b) whether priming-induced changes in syntactic comprehension lasted in the absence of an immediate prime, and (c) whether there is a significant correlation between individuals' priming effects and the change in their comprehension following priming. Methods & Procedures: Thirteen PWA and 13 age-matched control participants completed a pre-test, a production-to-comprehension priming block, and a post-test. In the pre- and post-tests, participants completed a sentence-picture matching task with sentences involving interpretations of an ambiguous prepositional phrase (e.g., The teacher is poking the monk with a bat). Participants were free to choose a picture corresponding to a high attachment (HA; e.g., the teacher is using the bat to poke the monk) or a low attachment (LA; e.g., the monk is holding the bat) interpretation. In the priming block, participants produced LA sentences as primes and then completed a sentence-picture matching task for comprehension targets, similar to the pre-test. Results: Age-matched controls and PWA showed a significant priming effect when comparing the priming block to the pre-test. In both groups, the priming effect persisted when comparing picture selections in the pre- and post-tests. At the individual level, age-matched controls who showed larger priming effects also selected more LA pictures in the post-test compared to the pre-test, indicating that the priming effect accounted for the magnitude of change from the pre- to post-test. This correlation was also found in PWA. Conclusions: These findings suggest that production-to-comprehension structural priming is effective and persistent in PWA and controls, in line with the view that structural priming is a form of implicit learning. Further, the findings suggest that syntactic representations are shared between modalities, and therefore, production influences future comprehension. Cross-modality structural priming may have clinical potential to improve sentence processing in PWA.