482 Identification of Candidate Neural Biomarkers of Obsessive-compulsive Symptom Intensity and Response to DBS

INTRODUCTION: Despite the success of DBS for the treatment of refractory OCD, there are currently no robust neural signatures for obsessive-compulsive (OC) symptoms or initial mood and energy improvements associated with DBS. This gap may be due to limited opportunities available for conducting intracranial electrophysiological recordings during natural symptom fluctuations. Recently available DBS platforms offer a way over this hurdle, allowing for streaming of intracranial local field potentials (LFP) at home and in the clinic. METHODS: We conducted longitudinal intracranial recordings in 10 patients with refractory OCD implanted with recording-capable DBS devices targeted to ventral capsule/ventral striatum (VC/VS). Five of the 10 were additionally implanted with ECoG strip electrodes over the orbitofrontal cortex (OFC). We captured LFP at home during naturalistic exposures to OCD triggers and in the clinic during variations in stimulation amplitude. RESULTS: All 5 participants who have completed the study so far are clinical responders to DBS therapy. Using the intracranial data collected during OCD exposures, we identified low delta-band power as a candidate neural biomarker of OC symptom intensity during symptom provocations (left VC/VS: R = -0.59, p = 0.01; right VC/VS: R = -0.56, p = 0.04). Electrophysiological analysis of acute response to stimulation revealed a narrow band increase in 30 Hz power specific to lateral OFC that was associated with increased talkativeness and approach behaviors that are typical harbingers of clinical response CONCLUSIONS: These signals have potential utility for classification of symptom intensity and increased mood and energy to enable adaptive DBS systems for OCD. Our data suggest that the neural biomarkers of these two clinical features might be separable, thus possibly allowing for simultaneous optimization of both.