Normative Brain Mapping of Interictal Intracranial EEG to Localise Epileptogenic Tissue
Abstract number :
V.027
Submission category :
3. Neurophysiology / 3G. Computational Analysis & Modeling of EEG
Year :
2021
Submission ID :
1825662
Source :
www.aesnet.org
Presentation date :
12/9/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:44 AM
Authors :
Peter Taylor, PhD - Newcastle University; Christoforos Papasavvas, PhD - Newcastle University; Thomas Owen, PhD - Newcastle University; Gabrielle Schroeder, PhD - Newcastle University; Frances Hutchings, PhD - Newcastle University; Fahmida Chowdhury, PhD - University College London; Beate Diehl, PhD - University College London; John Duncan, PhD - University College London; Andrew McEvoy, PhD - University College London; Anna Miserocchi, PhD - University College London; Jane de Tisi, PhD - University College London; Sjoerd Vos, PhD - University College London; Matthew Walker, PhD - University College London; Yujiang Wang, PhD - Newcastle University
Rationale: The identification of abnormal electrographic activity is important in a wide range of neurological disorders, including epilepsy for localising epileptogenic tissue. However, this identification may be challenging during non-seizure (interictal) periods, especially if abnormalities are subtle compared to the repertoire of possible healthy brain dynamics. Here, we investigate if such interictal abnormalities become more salient by quantitatively accounting for the range of healthy brain dynamics in a location-specific manner.
Methods: To this end, we constructed a normative map of brain dynamics, in terms of relative band power, from interictal intracranial recordings from 234 subjects (21,598 electrode contacts). We then compared interictal recordings from 62 patients with epilepsy to the normative map to identify abnormal regions. We hypothesised that if the most abnormal regions were spared by surgery, then patients would be more likely to experience continued seizures post-operatively.
Results: We first confirmed that the spatial variations of band power in the normative map across brain regions were consistent with healthy variations reported in the literature. Second, when accounting for the normative variations, regions which were spared by surgery were more abnormal than those resected only in patients with persistent post-operative seizures (t=-3.6, p=0.0003), confirming our hypothesis. Third, we found that this effect discriminated patient outcomes (AUC=0.75 p=0.0003). Normative mapping is a well-established practice in neuroscientific research.
Conclusions: Our study suggests that this approach is feasible to detect interictal abnormalities in intracranial EEG, and of potential clinical value to identify pathological tissue in epilepsy. Finally, we make our normative intracranial map publicly available to facilitate future investigations in epilepsy and beyond.
Funding: Please list any funding that was received in support of this abstract.: B.D. receives support from the NIH National Institute of Neurological Disorders and Stroke U01-NS090407 (Center for SUDEP Research) and Epilepsy Research UK. Y.W. gratefully acknowledges funding from Wellcome Trust (208940/Z/17/Z). P.N.T. is supported by a UKRI Future Leaders Fellowship (MR/T04294X/1). T.O. is supported by the Centre for Doctoral Training in Cloud Computing for Big Data (EP/L015358/1).
Neurophysiology