High Frequency Stimulation of the Centromedian Thalamic Nucleus to Abort Seizures and Interictal Discharges During Stereoelectroencephalography Evaluation (P5-1.007)

Abstract

<h3>Objective:</h3> To assess whether high frequency stimulation of the centromedian nucleus of the thalamus can disrupt seizures and/or interictal discharges. <h3>Background:</h3> There is growing evidence that subcortical structures, including the thalamus, are involved in seizure networks in patients with neocortical epilepsy. Responsive neurostimulation of the centromedian nucleus of the thalamus (CMT) has been shown to terminate seizures in case reports of patients with generalized and focal neocortical epilepsy [Burdette, et al. <i>Epilepsy and Behavior</i>, 2020]. However, to our knowledge, no prior reports have demonstrated the utility of stimulating the thalamus during a sEEG evaluation. We present two patients with refractory neocortical epilepsy who underwent sEEG evaluation including an electrode in the CMT. <h3>Design/Methods:</h3> Both patients underwent real-time high frequency stimulation (HFS) at CMT during runs of interictal discharges. Patient 1 was also stimulated during seizures. Stimulation settings for both patients were 50Hz, 0.3msec pulse duration, for 3 seconds. Patient 1 underwent stimulation at 2mA while Patient 2 was 1mA. For patient 1, seizure characteristics before and after stimulation were compared using a student’s t-test (duration) and Fisher exact test (apnea). <h3>Results:</h3> For Patient 1, HFS of the CMT successfully aborted 4 seizures. Compared to 11 seizures prior to stimulation, those with HFS were significantly shorter (9.5 vs. 20.5 seconds, p=0.018). The patient did not develop clinical apnea in any of the 4 seizures aborted with HFS, but did with all of the 11 seizures without stimulation (p=0.001). Stimulation during runs of interictal discharges was inconclusive. In Patient 2, HFS aborted runs of inter-ictal discharges in all 10 attempts. <h3>Conclusions:</h3> These cases demonstrate that stimulation of the CMT during sEEG evaluation can abort electroclinical seizures and potentially interictal discharges. This supports the idea that the CMT is involved in focal neocortical epilepsy networks. Stimulation during sEEG may be useful in predicting efficacy of thalamic neurostimulation. <b>Disclosure:</b> Dr. Nathan has nothing to disclose. Dr. Adney has received research support from NINDS. Joshua M Rosenow, MD, FAANS, FACS has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Boston Scientific Neuromodulation. Dr. Schuele has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Monteris. Dr. Schuele has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Neurelis. Dr. Schuele has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for SK Life Science. Dr. Schuele has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Jazz. Dr. Schuele has received personal compensation in the range of $50,000-$99,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Journal of Clinical Neurophysiology. Dr. Schuele has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Thomas Needham. Dr. Schuele has received research support from National Institute of Health. Dr. Gerard has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Greenwich Pharmaceuticals. The institution of Dr. Gerard has received research support from NIH/NINDS. The institution of Dr. Gerard has received research support from Xenon Pharmaceuticals. The institution of an immediate family member of Dr. Gerard has received research support from NIH. The institution of an immediate family member of Dr. Gerard has received research support from Novo Nordisk. The institution of Dr. Gerard has received research support from Eisai, Inc. (via Stanford University).