A preliminary investigation of neural changes following a morphology-based naming therapy in aphasia

Background: Many studies have aimed to uncover the neural mechanisms underlying language recovery in people with post-stroke aphasia (PWA), advancing our understanding of neural plasticity and guiding effective interventions. However, most research has been conducted on English-speaking individuals, and focused on either phonology or semantics. This study investigates neural changes associated with a novel Hebrew morphology-based naming therapy. Methods: Four Hebrew-speaking PWA received a twenty-session naming therapy focused on the Hebrew root morpheme. Participants were scanned using functional magnetic resonance imaging (fMRI) before and after treatment, while performing an overt picture naming task of morphologically complex treated and untreated words. Data analysis focused on changes in brain activation and connectivity within the language network following treatment. Results: Three participants, whose naming significantly improved following treatment, showed bilateral activation for picture naming before and after therapy, with a dominant left-hemisphere pattern. Nevertheless, these participants exhibited an increase in activation in varied bilateral areas but predominantly in the right-hemisphere for both treated and untreated words. Changes in connectivity were also varied mostly including enhanced inter-hemispheric and left intra-hemispheric connectivity. In contrast, the participant who did not benefit from treatment showed no significant activation changes for treated words and decreased activation and connectivity for untreated words. Conclusions: Neural changes observed in treatment responders suggest that our novel therapy induces neural plasticity. The changes found in both right and left hemispheres suggest that multiple mechanisms may be involved in the recovery process. The distribution of neural changes across different brain regions suggests that the effects of the treatment are not specific to morphological processing.