Arcuate fasciculus cortico-cortical and axono-cortical evoked potentials with post-resection excitability changes in...

To evaluate the feasibility and clinical utility of arcuate fasciculus cortico-cortical evoked potentials (AF-CCEP) and axono-cortical evoked potentials (AF-ACEP) during perisylvian supratentorial tumor surgery, and examine whether morphology changes serve as electrophysiological biomarkers of postoperative language function.

We analysed 19 patients with tumors involving or adjacent to the arcuate fasciculus across multiple tertiary centers. AF-CCEPs were elicited by monophasic stimulation toward the inferior frontal gyrus and recorded over the middle or posterior superior temporal gyrus; AF-ACEPs were obtained via subcortical bipolar stimulation. Primary outcomes explored N1 morphology pre- and post-resection, with subgroup analyses by tumor grade, location, montage, and anesthesia.

822 AF-CCEPs and 134 AF-ACEPs were acquired intraoperatively; 133 and 37 matched recordings were included for analysis, respectively. Post-resection N1 peak amplitude increased cohort-wide, while onset latency remained stable. One patient demonstrated signal loss associated with postoperative aphasia. AF-ACEP amplitudes were higher under general anesthesia, in higher-grade tumors, and with proximity to the AF on tractography.

AF-CCEP and AF-ACEP are feasible intraoperative adjuncts, with signal degradation associated with language morbidity. Post-resection amplitude increases may reflect intact AF conduction with increased cortical excitability following tumor removal.

When awake craniotomy is contraindicated, AF-CCEP and AF-ACEP may represent a viable alternative for monitoring AF integrity and reducing postoperative language morbidity.