1169 Disruption of Neural Periodicity Predicts Clinical Response after Deep Brain Stimulation for Obsessive-Compulsive Disorder

INTRODUCTION: Deep brain stimulation (DBS) for obsessive-compulsive disorder (OCD) improves symptoms in ∼66% of treatment-refractory patients. Recent advances in surgical neuromodulation have enabled chronic and continuous intracranial monitoring during everyday life. METHODS: Twelve patients with TR-OCD were implanted with a DBS generator in the ventral capsule/ventral striatum (VC/VS) that can record spectral power within a 5 Hz wide band (9 ± 2.5 Hz). We thus obtained chronic, passive recordings in this band at continuous 10-minute intervals in all participants (316 ± 128 days total duration per patient; 25 ± 20 days before VS DBS activation and 292 ± 136 days after). We developed our neurobehavioral models based on these neural recordings in an initial cohort of five patients and tested and validated them in a held-out cohort of seven additional patients. RESULTS: Prior to DBS activation, theta/alpha (9 Hz) power demonstrated a prominent circadian pattern and high degree of predictability. In non-responders with persistent symptoms, predictability of the neural data remained consistently high. In contrast, in responders who improved symptomatically, predictability was significantly diminished. In order to capture this feature, we fit a linear autoregressive model to the time series of 9 Hz power and computed a daily goodness of fit (R2) between the true and predicted data. The daily R2 values corresponding to the severe symptom state were significantly greater than those of the symptom unburdened state (p < 10-15). Using these daily predictability measures, we trained a classifier to predict clinical state with a leave-one-patient-out cross-validation strategy, achieving a balanced accuracy of 82%, well above chance level (p˜0). CONCLUSIONS: Our study demonstrates that changes in neural predictability serve as an accurate predictor of clinical status in patients with TR-OCD undergoing DBS therapy.