Deep brain stimulation of the anterior limb of the internal capsule reduced OCD symptoms in a small observational study.

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medRxiv Published April 16, 2026 Medically reviewed April 25, 2026 Study authors: Imtiaz, Z.; Kopell, B. H.; Olson, S.; Saez, I.; Song, H. N.; Mayberg, H. S.; Choi, K. S.; Waters, A.… DOI ↗ By Dr. Ji-eun Park, MD · Brain, Mind & Pain

Key Takeaway

Note that DBS of the ALIC reduced OCD symptoms in a small observational cohort, but results are preliminary.

This observational study investigated the effects of deep brain stimulation (DBS) targeting the anterior limb of the internal capsule (ALIC) in a population of 10 patients with clinically responsive obsessive-compulsive disorder. The study followed participants for six months to assess changes in primary and secondary outcomes. No comparator group was included, and the setting was not reported.

Regarding primary outcomes, OCD symptoms decreased on average by 40% across the subjects. However, symptom improvement was not universal; only one patient did not experience any improvement. Secondary outcomes measured alpha activity in the globus pallidus externus (GPe), which showed a significant decrease across both hemispheres. Notably, one patient never exhibited this alpha decrease in either hemisphere.

Safety and tolerability data were not reported in this study, and no adverse events or discontinuations were documented. The study design is observational, and key statistical measures such as p-values or confidence intervals were not reported. The small sample size of 10 patients limits the generalizability of these results. Consequently, the practice relevance remains uncertain, and these findings should be viewed as preliminary evidence rather than definitive proof of efficacy.

Study Details

EvidenceLevel 5

PublishedApr 2026

View Original Abstract ↓

Background: Deep brain stimulation (DBS) of the anterior limb of the internal capsule (ALIC) is an effective treatment for severe obsessive-compulsive disorder (OCD). Identifying brain readouts of positive response may guide further DBS optimization. Methods: We measured local field potential (LFP) changes from bilateral DBS leads in 10 OCD patients implanted at a uniform tractographic network target derived from prior DBS responders. We consistently stimulated dorsal lead contacts in the ALIC white matter, while recording LFP from the ventral lead contacts in grey matter of the anterior globus pallidus externus (GPe), a key node in the basal ganglia non-motor indirect pathway. Results: After six months of DBS, OCD symptoms decreased on average by 40% across subjects, along with a significant decrease in alpha activity across both hemispheres. Only one patient did not have an improvement of symptoms, and this was also the only patient to never exhibit an alpha decrease in either hemisphere. Conclusions: Our findings suggest that therapeutic ALIC DBS coincides with a stable decrease in limbic-cognitive GPe alpha power, which should be further investigated as a potential biomarker of sustained response.