Comparing Major Targets of DBS in Individuals with Treatment Refractory OCD: A Systematic Review

Abstract

Introduction: Individuals with obsessive-compulsive disorder experience lasting impairments that significantly lower their quality of life. Many neurostimulation procedures have formed a part of OCD treatment, including deep brain stimulation (DBS) - an established neurosurgical technique first introduced for treatment-refractory OCD (TROCD) involving implanting electrodes to send impulses to targeted brain regions. This paper aims to provide a systematic review of the current literature on DBS for TROCD, comparing six brain regions as potential targets.

Methods: The systematic review consisted of a literature search of primary research articles on PubMed, Google Scholar, MEDLINE, and Web of Science. The databases were assessed based on an inclusion and exclusion criteria which included patient health, comorbidities, diagnosis criteria, and age. In total, 17 articles were included.

Results: The stria terminalis, ventral capsule, and nucleus accumbens were identified as key areas targeted in the current literature for TROCD DBS. The inferior thalamic peduncle, medial forebrain bundle, and subthalamic nucleus were lesser studied regions, but presented with promising outcomes. Improvements in symptom severity for each target ranged from 35%- 54% in all six regions. Through this, scientists were able to speak upon the efficacy of the treatment and can now combine past knowledge to create tests with even better functioning outcomes. Moreover, connections between neuronal pathways can now be made to help in better understanding complexities of TROCD.

Discussion: Improvements in OCD symptoms were most promising for DBS to the ventral capsule and inferior thalamic peduncle. Common secondary outcomes included reduced anxiety and depression, and select studies also reported on improved quality of life and daily functional ability. Common adverse effects across the different targets were hypomania mood and anxiety-related events, with a large variety of adverse events across targets.

Conclusion: The ideal target for TROCD DBS is unclear due to the large variability of Y-BOCS scores, secondary outcomes, and adverse effects reported. Future directions include personalized targets within the regions, stimulating multiple targets in the same patient, further investigating the potential of targeting the medial forebrain bundle, and studying the effects of DBS on long-term quality of life.