NCOG-32. RELATIONSHIPS BETWEEN INTRAOPERATIVE TASK-BASED GAMMA BAND ELECTROCORTICOGRAMS, DIRECT ELECTRICAL STIMULATION, AND COGNITIVE-LINGUISTIC OUTCOME FOLLOWING AWAKE BRAIN TUMOR RESECTION

Abstract

Abstract BACKGROUND As an adjunct to direct electrical stimulation (DES), intraoperative electrocorticography (ECoG) can aid detection of language-eloquent cortex. However, it is unclear how surgical impact upon mapping findings relates to cognitive-linguistic outcomes. METHODS Ten patients underwent awake craniotomy for tumor resection with ECoG and DES language mapping. Mapping utilized iPad stimulus presentation coupled to an electrode array capable of both recording ECoG activity and delivering DES. Time-frequency gamma band activations were visualized (Early, Long, Late, Double Peak) for 3 naming paradigms (Object, Action, Auditory). DES was also conducted for each task. Mapping results were overlayed on postoperative MRI to examine proximity to parenchymal trauma (cavity, sulcal displacement). Patients completed cognitive-linguistic testing [WAB-R (N=3) or Neuropsychological Assessment (N=7)] prior to surgery and <2 months postoperatively. Patients with persisting aphasia at 6-month follow-up were also identified. RESULTS Postoperative language decline was found in 50% of patients, with 30% showing worsening (>1SD) in Naming and Phonemic Fluency, and 60% in Semantic Fluency. Surgery impacted ECoG features in 60% of patients and DES arrest sites in 30%. A trend was observed where Early and Late Object naming ECoG features were associated with Semantic Fluency decline [rpb(5)=-.69, p=.067]. Arrest during Auditory naming DES <1 cm of surgical effect was associated with decline in Abstraction [rpb(5)=-.83, p=.042; FET, p=.029] and Semantic Fluency [rpb(5)=-.87, p=.012; FET, p=.024]. Excluding the 3 transsulcal surgeries, arrest during Auditory naming DES <1 cm of resection was associated with general language decline [FET, p=.047]. All 3 patients with persisting aphasia had Auditory naming arrest <1 cm of resection and 2/3 patients had Object naming ECoG features resected. CONCLUSIONS While preliminary, results suggest that surgical proximity to ECoG and DES mapping results may inform risk of surgically-acquired cognitive-linguistic decline. Findings support the potential of multimethod-multitask intraoperative language mapping.