Poster B54, Sunday, March 25, 8:00-10:00 am, Exhibit Hall C
Mechanisms of neural plasticity during recovery from sentence processing deficits in chronic stroke-induced aphasia: an fMRI study
Elena Barbieri1, Jennifer E. Mack1, Brianne M. Dougherty1, Eduardo Europa1, Cynthia K. Thompson1; 1Northwestern University, Evanston, IL
The role of the right hemisphere (RH) in aphasia recovery is still debated. While studies using repetitive transcranial magnetic stimulation (rTMS) have supported theories assigning the RH a maladaptive role in aphasia recovery, recent neuroimaging studies have suggested that changes in the RH neural activation or in functional connectivity may be associated with recovery of language functions (Kiran et al., 2015). The present study investigated the role of the RH in recovery of sentence processing in 11 participants with chronic stroke-induced aphasia who underwent a 3-month sentence comprehension/production treatment protocol focused on passive sentences (Treatment of Underlying Forms, Thompson & Shapiro, 2005) and 4 non-treated participants. At both timepoints, all participants underwent a block-design fMRI task employing a picture-verification task, in which comprehension of active and passive sentences was alternated with blocks of a control condition (scrambled picture presented with reversed speech). Increased activation (upregulation, p<.001 unc.) from pre (T0) to post-treatment (T1) was observed in the treatment group only. Region-of-interest (ROI) analyses showed significant upregulation (p<.01) in ‘good responders’ (i.e., participants exhibiting significant gains in comprehension and/or production), within the RH homologues of regions associated with sentence processing. Laterality indices computed for good responders at both timepoints indicated a shift from bilateral activation for passive>control at T0 to a right-lateralized activation at T1 within the sentence processing ROIs, and no shift within a subset of domain-general ROIs (dorsal attention network) The study demonstrates that the RH contributes to the restoration of normal-like sentence processing patterns in chronic aphasia.
Topic Area: LANGUAGE: Syntax