Deep Brain Stimulation for Epilepsy: Optimal Targeting and Clinical Outcomes.

Background: Deep brain stimulation (DBS) has been investigated for patients with drug-resistant epilepsy who are not candidates for resective surgery. Because different types of epilepsy involve different brain networks, numerous DBS targets have been explored.

Methods: To provide a comprehensive overview of this expanding literature, we conducted a systematic review of studies for DBS in epilepsy, collecting data on surgical targets, individual disease characteristics, outcomes, and precise electrode placements. DBS electrode coordinates were gathered into a common template space and related to clinical outcomes.

Findings: We included 124 studies, corresponding to 1,210 patients and 20 distinct surgical targets. While the anterior (ANT) and centromedian (CM) nuclei of the thalamus remain the most studied, we also review less commonly used targets that show promise for specific forms of epilepsy and may warrant further investigation. Substantial variability in targeting strategies and electrode placement was observed within each of the target regions. Importantly, significant relationships between stimulation location and outcomes were identified for ANT- and CM-DBS. For ANT-DBS, shorter distance to the mammillothalamic tract junction was associated with greater seizure reduction on both study- and patient-level analyses (r=-0.55, p<0.001 and r=-0.51, p<0.001, respectively). For CM-DBS, localization effects may be dependent on the form of epilepsy, with stimulation of the parvocellular CM being associated with better outcomes in generalized epilepsy.

Interpretation: Our results emphasize the importance of accurate targeting in DBS for epilepsy. Our database and atlas of DBS targets are made publicly available, potentially serving further meta-analytical work.