145 Encoding Brain Dynamics: Neuropsychological Test Scores as Predictors of iEEG Spectral Features in Epilepsy

Abstract

INTRODUCTION: Intracranial EEG is a valuable tool for investigating the neural mechanisms underlying medically refractory epilepsy (MRE). Despite the advances made in understanding the condition, there is a lack of research exploring the relationship between iEEG data and neuropsychological test performance in MRE patients. METHODS: We performed a retrospective analysis of resting-state iEEG data from 70 MRE patients, extracting spectral features from 4.4 million 10-second time windows across 5201 electrodes. Using MATLAB and FieldTrip toolbox, we processed the data and used two brain atlases for probabilistic electrode assignment. Neuropsychological test scores were corrected for demographic factors. Relationships between preoperative neuropsychological test scores and spectral features were explored using nested hierarchical generalized linear mixed effects (GLME) models, focusing on the hippocampus. RESULTS: We found significant associations between neuropsychological tests and hippocampal power spectral densities (PSDs). Rey Auditory verbal learning test (RAVLT) recognition correct and short-term retention percentages were significantly associated with relative power (RP) in the beta-range (p < 0.05, FDR-corrected). The Boston naming test and Trail Making Test (TMT)-A finishing time showed significant associations with high-beta/low-gamma PSD (p < 0.05, FDR-corrected). TMT-B errors are positively correlated with delta/theta RP (p < 0.05, FDR-corrected). CONCLUSIONS: Our study provides novel insights into the relationship between iEEG spectral features and neuropsychological test performance in MRE patients. The findings suggest that the heterogeneity in spectral features may explain relevant cognitive performance, highlighting the biological basis and circuits of neuropsychological testing.