Multisite Intrathalamic Recordings to Study the Propagation of Seizures in the Human Brain
Abstract number :
2.002
Submission category :
3. Neurophysiology / 3A. Video EEG Epilepsy-Monitoring
Year :
2022
Submission ID :
2205116
Source :
www.aesnet.org
Presentation date :
12/4/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:28 AM
Authors :
Teresa Wu, MD – Stanford University, Stanford School of Medicine/ Sutter Health Comprehensive Epilepsy Center; Neda Kaboodvand, PhD – Neurology and Neurological Sciences – Stanford University, Stanford School of Medicine; Ryan McGinn, MD – Neurology and Neurological Sciences – Stanford University, Stanford School of Medicine; Vivek Buch, MD – Neurosurgery – Stanford University, Stanford School of Medicine; Josef Parvizi, MD, PhD – Neurology and Neurological Sciences – Stanford University, Stanford School of Medicine
Rationale: While early evidence is emerging in human studies highlighting thalamocortical dynamics in focal seizures, differential involvement of various thalamic subregions at ictal onset and in seizure propagation remains unknown. This is increasingly relevant as thalamic targets have shown promise in neuromodulation treatments of drug resistant seizures.
Methods: We used a novel stereo-EEG implantation protocol for multisite intrathalamic sampling along with many cortical regions of interest. The seizure onset zones (SOZ) were determined visually and the propagation of seizures to thalamic sites was determined by two modalities: visual analysis of seizures by three independent experts, and the measure of thalamic evoked potentials after repeated single pulse stimulation of the clinical SOZ.
Results: The procedure was safe, with no hemorrhages or adverse events associated with multisite thalamic electrodes. In total, we studied 104 seizures across 9 patients. Of these, 63 seizures had a clearly focal SOZ in the hippocampus, amygdala, insula, or inferior temporal cortex. By contrast, 41 seizures had a broad SOZ involving multiple cortical regions. Across these seizures, two main observations were made by visual analysis. First, the seizures may propagate to different thalamic nuclei despite having the same cortical onset regions. For example, in 51 seizures originating from the inferior temporal cortex, 21 seizure were labeled as first propagating to the anterior thalamic (ANT), 15 to the pulvinar (Pulv), and 15 to ANT and Pulv simultaneously. Second, anatomical location of the SOZ was not predictive of the thalamic subregion to be involved first. For instance, 6 seizures with SOZ in the insula propagated first to the Pulv; 13 seizures with “broad” SOZ in the frontotemporal regions also propagated first to the Pulv. Study of evoked responses in 5/6 patients, largely validated the findings captured during expert visual inspection and highlighted an interesting profile of thalamic interplay with various cortical regions labeled as SOZs.
Conclusions: In patients who are candidates for neuromodulation therapies, multisite intrathalamic recordings may safely identify the key thalamic region involved in seizure propagation in that individual’s brain, which in turn may help identify a more optimal target for neuromodulation at the individual patient level.
Funding: Not applicable
Neurophysiology