The role of right hemisphere in second language processing: Insights from a case study

Direct electrical stimulation (DES) during awake brain surgery offers a unique opportunity to explore the neural basis of language. Although evidence from existing studies has shown increased involvement of the non-dominant (right) hemisphere in second language processing (particularly in late bilinguals) evidence from DES studies remains limited. We report the case of a 36-year-old right-handed late bilingual female (L1: Bulgarian; L2: Greek), who underwent awake craniotomy to treat an arteriovenous malformation beneath the right middle frontal gyrus (rMFG). Preoperative assessments revealed no clinically significant cognitive or linguistic deficits. During intraoperative mapping, DES on rMFG elicited anomias and phonemic paraphasias in L2, but not in L1, a finding consistent with reports in the literature regarding the role of rMFG in the episodic memory and the mental lexicon. Although coming from a single case, our findings provide direct evidence for the role of the rMFG in supporting second language processing in late bilinguals.