Frequency Band Specific Directed Connectivity Patterns in Focal Epilepsy: A Single Pulse Electrical Stimulation Study
Abstract number :
2.048
Submission category :
3. Neurophysiology / 3E. Brain Stimulation
Year :
2022
Submission ID :
2204276
Source :
www.aesnet.org
Presentation date :
12/4/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:24 AM
Authors :
Aarushi Negi, – Vanderbilt University; Graham Johnson, B.S. – Department of Biomedical Engineering – Vanderbilt University; Derek Doss, B.E. – Department of Biomedical Engineering – Vanderbilt University; Jared Shless, B.S. – Department of Neurological Surgery – Vanderbilt University Medical Center; Danika Paulo, M.D. – Department of Neurological Surgery – Vanderbilt University Medical Center; Victoria Morgan, Ph.D. – Department of Biomedical Engineering – Vanderbilt University; Sarah Bick, M.D. – Department of Neurological Surgery – Vanderbilt University Medical Center; Dario Englot, M.D., Ph.D. – Department of Neurological Surgery – Vanderbilt University Medical Center
Rationale: Previous studies have found that seizure-generating regions (“seizure onset zones” or SOZs) and propagation zones (PZs) exhibit high directed (inward and outward) connectivity to the rest of the brain during single pulse electrical stimulation (SPES).1,2 However, frequency-specific components of network connectivity have not been well-characterized with SPES. Our investigation seeks to assess SOZ, PZ, and non-involved region directed connectivity across multiple frequency bands with SPES to elucidate electrographic “signatures” of each zone to facilitate more accurate SOZ localization and improve understanding of network connectivity in focal epilepsy._x000D_
Methods: We included 23 patients who underwent pre-surgical workup of medically refractory focal epilepsy. Patients underwent stereotactic electrode implantation and were consented for SPES on all gray matter adjacent bipolar pairs of contacts (1 Hz, 10-second pulse train of 300 microsecond biphasic pulses at 3 mA). Directed connectivity of SOZs, PZs, and non-SOZs was analyzed in four frequency bands: theta (4-7 Hz), alpha (8-12 Hz), beta (13-30 Hz), and gamma (31-80 Hz). Band-specific connectivity was measured by relative band power change from pre-stimulation baseline - which indicates frequency band power change as a proportion of whole band power - over a 5-505 millisecond post-stimulation time window._x000D_
Results: The theta band shows differences in directed connectivity between SOZs, PZs, and non-SOZs (Figure 1A, p< 0.01); SOZs and PZs have greater outward than inward connectivity while non-SOZs have little difference in inward versus outward connectivity. In the beta band, SOZs and PZs have higher inward than outward connectivity while non-SOZs show slightly greater outward than inward connectivity (Figure 1C, p< 0.05). In the gamma band, SOZs exhibit greater inward than outward connectivity relative to PZs (Figure 1D, p< 0.05)._x000D_
Neurophysiology