460 Characterization of a Candidate Responsive Electrophysiological Biomarker in Sensing-Enabled Deep Brain Stimulation of the Ventral Capsule/Ventral Striatum for Obsessive-Compulsive Disorder

INTRODUCTION: Deep brain stimulation (DBS) may benefit from the use of neural biomarkers, which can bolster the effectiveness of therapy; however, no such biomarker is known for obsessive-compulsive disorder (OCD). METHODS: 11 patients with sensing-enabled ventral capsule/ventral striatum DBS for OCD were followed. Baseline pre-treatment snapshot surveys of power spectral densities (PSDs) were obtained and were aperiodic-corrected using the fitting oscillations and one-over-f method (FOOOF). These PSD snapshots were repeated at follow-up. Patients indicated episodes of OCD symptom flare-ups, triggering the capture of an event-locked PSD. In addition, an in-clinic review of stimulation combinations was conducted while streaming the alpha-band LFP while collecting acute symptom rating scales. Lastly, chronic recordings were obtained and correlated with changes in OCD severity over time. RESULTS: All 11 patients demonstrated a peak in the alpha-band (8–12.5 Hz) in baseline pre-treatment surveys. 6 of the 7 patients with usable follow-up snapshot PSD surveys, showed suppression of alpha power correlating with symptom improvement. 4 patients reported at-home symptomatic events, and all 4 patients demonstrated a broadband increase in power, present in the alpha-band but also including high theta- and low beta-bands. 3 patients had available chronic alpha power tracking over time and all demonstrated alpha power suppression correlated with symptomatic improvement. In-clinic acute alpha power response was mixed, with 3 of 7 patients demonstrating acute dose-dependent suppression of alpha power which correlated with increasing stimulation amplitude; the data of the remaining 4 patients was unusable due to stimulation artifact. CONCLUSIONS: Our findings suggest that a peak in the alpha band may be a suitable candidate responsive electrophysiological biomarker to identify the OCD disease state. The clinical utility of acute alpha power response merits further investigation.