A potential therapeutic role of unilateral anterior thalamic deep brain stimulation in epileptic spasms: A case report

Abstract

Objective Deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS) is an established palliative therapy for drug-resistant focal epilepsy; however, its efficacy for epileptic spasms (ES) and the clinical utility of unilateral stimulation remain unclear. To address these issues, we report a case of drug-resistant focal epilepsy with ES treated with unilateral ANT-DBS. Case An 18-year-old right-handed male with focal cortical dysplasia type I had long-standing drug-resistant epilepsy. Despite multiple resective and palliative surgeries—including right frontal disconnection, corpus callosotomy, right anterior temporal lobectomy, and vagus nerve stimulation—daily ES, weekly focal impaired consciousness seizures (FIC), and monthly focal-to-bilateral tonic-clonic seizures (FBTC) persisted. Presurgical evaluation suggested an epileptic focus in the left temporal lobe for FIC/FBTC. ANT-DBS was planned for seizure alleviation. Lead implantation on the right side was considered unfavorable because of marked postsurgical atrophy. Therefore, unilateral ANT-DBS lead implantation on the left side was performed. Results After implantation, ES frequency transiently decreased (median 0.46 seizures/day) but later increased during follow-up. Stimulation was initiated on postoperative day 22. After the stimulation amplitude reached ≥2.0 mA (postoperative day 92), the median spasm frequency decreased again to 0.31/day, lower than the preoperative baseline of 0.75/day (58.1% reduction; p = 0.012). FIC frequency also decreased from 0.21/day to 0.09/day (60.0% reduction; p = 0.121). Significance Unilateral ANT-DBS was associated with a clinically meaningful reduction in ES in this highly refractory case, suggesting a potential therapeutic role even when bilateral implantation is not feasible.