Although repetitive transcranial magnetic stimulation (rTMS) can enhance aphasia recovery when paired with language therapy, outcomes vary widely. Aphasia, or the loss of language, affects 20–40% of stroke survivors and often leaves individuals struggling to produce full, descriptive sentences in daily life. While there is no cure, language therapy seeks to address these deficits through structured training. Research has shown that rTMS can extend recovery beyond therapy alone, yet responses vary: some patients improve significantly months later, others only briefly, and some not at all.

This study examined whether lesion location helps explain variability in response to rTMS, and whether such regions generalize across word class (nouns vs. verbs). Participants with chronic aphasia (N=27) were assessed based on correct scores in Constraint Induced Language Therapy (CILT) at baseline and six months post-treatment (therapy and TMS). Within active and sham stimulation groups, patients were classified as responders or non-responders based on score change. Overlap and subtraction analyses revealed regional differences between responders and non-responders, diverging along two axes: active vs. sham stimulation and nouns vs. verbs. These patterns involved gray matter regions as well as white matter tracts, though their interpretation is limited by small sample size and methodological variability.

These findings suggest that certain brain structures may be necessary for patients to benefit from rTMS or therapy as a whole. Identifying these regions, once validated in larger samples, could provide greater specificity in language treatment and recovery strategies.