CNSC-24. REAL-TIME HIGH-DENSITY ECOG MAPPING OF SENSORIMOTOR REGIONS AND CONSCIOUSNESS DIFFERENTIATION IN PERI-ROLANDIC GLIOMA SURGERY

Abstract INTRODUCTION Accurately mapping sensorimotor regions is crucial for preserving motor and sensory functions in the treatment of gliomas located in the peri-Rolandic areas of the brain. OBJECTIVE We examined the use of high-density electrocorticography (ECoG) for passive mapping of sensorimotor regions in treating peri-Rolandic gliomas by analyzing the spatial-temporal and spectral features of real-time somatosensory evoked potentials (SSEPs), and their spectral patterns in differentiating states of consciousness. METHODS During surgery, SSEPs were recorded using high-density ECoG on fourteen patients (n=14), both in anesthetized and awake states. Neural data from 0.6Hz median nerve stimulation were captured at 2.4kHz and processed in real-time using MATLAB Simulink. The system displayed SSEPs’ peak activations as a 2D heat map on a screen, particularly around the 20ms time point (N20), and generated the spectral power in the gamma range using the Stockwell transform. Accuracy in delineating the central sulcus (CS) was assessed using the ROC curve, and paired t-tests compared gamma oscillations between states of consciousness. RESULTS Patients consistently showed clear discrimination between anterior and posterior channels at the 20ms time point, with 93.6±14.9% accuracy. Color contrast delineated the CS, correlating with the sulcus in the 3D reconstructed magnetic resonance imaging of each patient. Late gamma (60–250 Hz) modulation occurred 50 ms after stimulation onset, extending up to 250 ms in the primary somatosensory area. It was suppressed in the anesthetized state and significantly increased in the awake state (delineation accuracy: 81±10.3% and 91±13.4%, respectively). CONCLUSIONS These results demonstrate that SSEPs and gamma modulations can delineate sensorimotor areas and assess consciousness, significantly impacting neurosurgical planning.