Abstracts

A Novel Directional and Scalable (DiSc) Electrode for Recording Epileptic Markers in Subjects Undergoing Resection

Abstract number : 3.147
Submission category : 2. Translational Research / 2B. Devices, Technologies, Stem Cells
Year : 2025
Submission ID : 1195
Source : www.aesnet.org
Presentation date : 12/8/2025 12:00:00 AM
Published date :

Authors :
Presenting Author: Jude Savarraj, PhD – McGovern Medical School, University of Texas Health Science Center at Houston

Adeel Ilyas, MD – McGovern Medical School, University of Texas Health Science Center at Houstont
Amada Abrego Mancilla, MS – McGovern Medical School, University of Texas Health Science Center at Houstont
John Seymour, PhD – University of Texas Health Science Center at Houston
Nitin Tandon, MD – McGovern Medical School, University of Texas Health Science Center at Houston

Rationale: The DiSc electrode array offers a novel method for recording local field potentials (LFPs) with superior spatial resolution and directional sensitivity by combining the minimally invasive form of standard sEEG electrodes with radially distributed microelectrodes for simultaneous multi-scale recordings. Previous studies show that DiSc electrodes provide improved signal-to-noise ratios, directional sensitivity, and decoding accuracy over conventional ring electrodes in rodents, but this is the first report in humans. We tested DiSc electrodes in epileptic patients undergoing resection to assess the ability of DiSc to record epileptic markers like interictal spikes.

Methods: Intraoperative LFP recordings were conducted on two patients with medically refractory epilepsy: subject-1 (59, F) had a DiSc electrode in the hippocampus, and subject-2 (46,F) had a DiSc electrode in the right frontal operculum with simultaneous 8-channel ECoG surface recordings. The recordings were manually annotated for IEDs using a custom software. Spike morphology analysis was performed using UMAP dimensionality reduction followed by K-means clustering. Spike co-occurrence was defined as temporal overlap within ±100 ms windows.

Results: In subject-1, we observed 509 spikes (spiking rate: 28.6 spikes/minute) over the 17.8-minute recording period. Spike morphology analysis of DiSc identified four distinct clusters: Cluster 1 (305 spikes, 60.0%), Cluster 2 (120 spikes, 23.6%), Cluster 3 (61 spikes, 12.0%), and Cluster 4 (22 spikes, 4.3%), suggesting that the DiSc electrode effectively captured activity from diverse neuronal populations within the hippocampal epileptogenic zone. In subject-2, we observed 41 spikes (spiking rate: 7.3 spikes/minute) over a 5.58 minute recording period. A total of and 66 ECoG spikes were identified across 8 surface channels (spiking rate: 11.8 spikes/minute). Co-occurrence analysis showed that 25.8% of ECoG spikes (17/66) temporally correlated with DiSc spikes within the 100ms window, while 34.1% of DiSc spikes (14/41) correlated with ECoG activity. Most epileptiform activity occurred independently, with 74.2% of surface spikes (49/66) showing no corresponding deep activity and 65.9% of DiSc spikes (27/41) occurring without surface correlates. 

Conclusions: We demonstrate the utility of DiSc electrodes for LFP recording in patients undergoing unergoing resection surgery. A significant portion of independent epileptic activity (65-74%) between DiSc depth electrodes and cortical surface ECoG in was observed, while partial co-occurrence (26-34%) suggests functional connectivity. DiSc hippocampal analysis showed higher spike rates and morphological diversity with distinct spike clusters. The methodology establishes a framework for analyzing multi-electrode interactions and validates DiSc technology's potential for improving epileptogenic zone localization, with future studies needed to confirm its utility for diagnosis and surgical planning.

Funding: NIHNIH, , NINDS 5UG3NS125487-02 

Translational Research