Facial Action Units and Head Dynamics in Longitudinal Interviews Reveal OCD and Depression severity and DBS Energy

Abstract

Neuromodulation therapy, specifically Deep Brain Stimulation (DBS) of the ventral capsule/ventral striatum (VC/VS), is promising treatment for severe and intractable obsessive-compulsive disorder (OCD). To assess treatment response to DBS, reliable biomarkers are needed. We explored the hypothesis that facial action units and head dynamics in an interview context reveal severity of OCD, related depression, and DBS energy in participants undergoing DBS treatment. Participants were 5 patients (3 females, 2 males) with implanted DBS to VC/VS. They were recorded during brief open-ended interviews by a clinician at pre- and post-surgery baselines and then at 3-month intervals following activation of the DBS electrodes. Facial action units and head dynamics were assessed using AFAR (Automatic Facial Affect Recognition). OCD severity was assessed using clinical interview (YBOCS-II) and depression symptoms were assessed using participant self-report (BDI). After testing for multicollinearity and dropping highly-correlated features, a linear mixed-effects model using chi-square feature selection predicted 61% of the variation in YBOCS-II; 59% of the variation in BDI; and 37% of the variation in delivered energy by DBS to VC/VS. These findings suggest that automatically detected facial action units and head dynamics are potential biomarkers of OCD, depression se verity, and DBS energy.