Objective: To evaluate the longitudinal evolution of FOG in patients with PD undergoing bilateral STN-DBS using validated clinical scales for gait and balance assessment.

Background: FOG is one of the most disabling axial symptoms in Parkinson’s disease (PD) and a major contributor to falls, loss of independence and impaired quality of life. Although STN-DBS effectively improves motor fluctuations, its effects on FOG remain heterogeneous and insufficiently characterized over long-term follow-up.

Method: This prospective multicenter observational study included 11 patients with advanced PD who underwent bilateral STN-DBS across six Spanish centers. Assessments were performed preoperatively and at 6 months, 1, 2 and 3 years postoperatively. Clinical evaluations were conducted under four conditions: OFF med/OFF stim,OFF med/ON stim, ON med/OFF stim, and ON med/ON stim. Outcome measures included the FOG score, MDS-UPDRS parts III and IV, Mini-BESTest, Hoehn & Yahr, Falls diary, MoCA test, and CGI-I. Dopaminergic medication (LEDD) and stimulation parameters were recorded.

Results: STN-DBS was associated with a significant reduction in dopaminergic medication requirements (p=0.001) and sustained improvement in overall motor symptoms throughout the 36-month follow-up. FOG scores significantly improved at 1 year under stimulation (p<0.05). Although improvements were observed at other follow-up points, they did not reach statistical significance, likely reflecting baseline variability and the limited sample size. Balance performance improved significantly during the first two postoperative years, and Hoehn & Yahr  improved under stimulation across follow-up. No increase in fall frequency or cognitive decline was observed. Both clinicians and patients reported sustained clinical improvement.

Conclusion: STN-DBS was associated with a significant improvement in FOG during the first postoperative year under stimulation. Although statistical significance was not maintained at later follow-up points—likely reflecting sample attrition and variability over time—a persistent trend toward improvement was observed. In addition, STN-DBS provided sustained motor benefits and significant reductions in dopaminergic medication without increased fall risk or cognitive decline. Overall, STN-DBS demonstrated a favorable safety and efficacy profile for gait and balance outcomes in PD patients over mid-term follow-up.

References: *Parts of this work were previously presented at the 3rd Expert Summit on the Future of DBS (Würzburg, Germany).

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MDS Abstracts - https://www.mdsabstracts.org/abstract/longitudinal-evolution-of-freezing-of-gait-after-stn-dbs-in-parkinsons-disease-insights-from-the-gait-dbs-multicenter-study/