EP 38. Subthalamic nucleus Deep Brain Stimulation (STN-DBS) reduces freezing of gait in Parkinson’s disease in the VANTAGE prospective, multi-center trial

Abstract

Background Deep Brain Stimulation (DBS) is effective for Parkinson’s disease (PD) symptom relief; however, improvement of freezing of gait (FOG) remains under debate. Some studies indicate STN-DBS alleviates FOG, while others suggest an association of STN-DBS with worsening of gait and balance or even induction of FOG. The VANTAGE study assesses motor improvement in moderate-to-severe PD following bilateral STN-DBS using a new, implantable, rechargeable, multiple-source, 16-output (supporting two 8-contact leads), constant-current, CE-marked DBS System. We report the effects of STN-DBS on FOG in this cohort of PD subjects. Methods VANTAGE is a monitored, prospective, multi-center, non-randomized, open-label interventional trial, sponsored by Boston Scientific Corporation. FOG was characterized with UPDRS-II item 14, the freezing of gait questionnaire (FOGQ) and a walking test known to provoke FOG pre and post-surgery. Data collection included FOGQ at Baseline and 26 weeks post-implantation, and the walking test at Baseline, 12, 26, and 52 weeks post-implantation. The walking test was videotaped and rated remotely by an independent rater (CS), blinded to the subject’s implantation status. Results Thirty-eight subjects, of the forty implanted, were analyzed with FOGQ data. The FOGQ showed significant improvement at 26 week follow up versus baseline derived from UPDRS-III item 29 and UPDRS II item 14. FOGQ (item 3) data at 26 weeks versus baseline indicated 12 freezers remained freezers, 15 freezers turned to non-freezers, 10 non-freezers remained non-freezers, and one non-freezer turned to a freezer. The walking test was performed by 29 of 38 subjects at baseline during medication off. Thirteen subjects showed FOG-episodes off medication at baseline and improved after L-Dopa intake. Postoperatively, the total walking time, FOG episode occurrences, and total time spent frozen were reduced at week 12, 26, and 52 compared to baseline during medication off. Conclusions FOGQ and walking test data demonstrate that STN-DBS can reduce FOG occurrence and severity at 26 weeks postoperatively with constant effects at week 52. Follow-up data will help to understand if improvement on FOG persists long term.