An advancement of intraoperative language mapping in awake craniotomy

Direct electrical stimulation (DES) during awake craniotomy is the gold-standard for language mapping; however, conventional tasks (e.g. counting, object naming, reading) provide limited sensitivity to grammatical and sentence-level processes. The present study introduces the first intraoperative application of the English Verb and Noun Test for Perioperative testing (VAN-POP), a sentence-based paradigm designed to probe object and action naming with finite verbs in past and present tense. VAN-POP was administered to four UK English-speaking patients undergoing awake craniotomy for WHO grade II-III gliomas involving frontal, temporal, or parietal regions. Language-positive sites were identified in three patients, and real-time monitoring revealed language disruptions in three patients. DES elicited action naming disruptions in two patients. Middle and inferior frontal stimulation induced tense errors and verbal-visual paraphasias, whilst angular gyrus stimulation induced speech arrest. During resection, three patients exhibited action naming disruptions, including semantic and morphosyntactic errors, anomia, and delays. Postoperatively, no patients showed clinically significant deficits requiring speech and language therapy. These findings demonstrate that VAN-POP is feasible for intraoperative use and increases sensitivity to grammar-related cortical sites beyond conventional mapping approaches. Incorporating finite verb production within DES protocols may improve delineation of language networks, supporting better preservation of function.