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Case Report: Successful treatment of drug-resistant epilepsy with unilateral deep brain stimulation of the anterior nucleus of the thalamus

Year: 2026

Type: article

Abstract: Background Deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS) is an established palliative treatment for drug-resistant epilepsy (DRE) and is conventionally performed bilaterally. However, the efficacy of unilateral ANT-DBS remains unclear. We report a patient with DRE who underwent unilateral ANT-DBS because of an epileptogenic network predominantly involving one side and anatomical constraints precluding electrode implantation on the contralateral side. Methods A 29-year-old female underwent comprehensive presurgical evaluation, including seizure semiology assessment, video-electroencephalography (EEG), computed tomography, and magnetic resonance imaging. She developed DRE following multimodal treatment for a suprasellar germ cell tumor during childhood. Despite multiple antiseizure medications and vagus nerve stimulation, she continued to experience approximately 10 habitual seizures per day. Results Seizure semiology was characterized by asymmetric tonic posturing of the limbs lasting 10–30 s, followed by an atonic phase. EEG findings indicated a widespread epileptogenic network predominantly involving the right frontal and temporal areas. Brain imaging showed severe left hemispheric atrophy, marked widening of the left subdural space, and a pre-existing shunt system, which prevented identification of the left ANT. Therefore, DBS implantation was performed in the right ANT alone. Stimulation was initiated 7 days after surgery at an intensity of 2 mA. Following initiation of right ANT stimulation, seizure frequency decreased from approximately 10 to one per day, likely due to a microlesioning effect. Thereafter, right ANT stimulation was associated with a sustained seizure reduction of approximately 60%. Postoperative EEG demonstrated a reduction in interictal epileptiform discharges. The clinical benefit was maintained at the 9-month follow-up, with no surgery- or stimulation-related adverse events were observed. Conclusion Unilateral ANT-DBS can provide clinically meaningful seizure control in carefully selected patients whose predominant epileptogenic network is localized to one cerebral hemisphere. This approach may represent a feasible therapeutic option when anatomical or surgical constraints prevent conventional bilateral ANT electrode implantation. Further studies with larger patient cohorts and longer follow-up periods are required to clarify the indications, durability, and efficacy of unilateral ANT-DBS.

Source: Frontiers in Neuroscience

DOI: 10.3389/fnins.2026.1978183