Objective – To evaluate the effect of bilateral deep-brain stimulation (DBS) in the subthalamic nucleus (STN) on balance performance in patients with severe Parkinson's disease (PD), when tested without anti-parkinsonian medication.
Material and methods – Thirty-one patients (median age 65 years, range 50–77) were included. Assessments were made after 10–12 h withdrawal of medication, before and 6 and 12 months after surgery. Postoperative evaluations were performed with DBS on and off. Balance performance was evaluated with the Berg Balance Scale (BBS). Motor symptoms and postural stability (item 30) were assessed with the Unified Parkinson's Disease Rating Scale (UPDRS III).
Results – DBS in STN improved balance performance as well as postural stability and motor symptoms significantly (P ≤ 0.001). Seventy per cent of the patients improved their total score of the BBS with DBS on compared with DBS off. Thus, at 6 months their median improvement was 6 points (q1–q3, 4–11) and at 12 months 4 points (2.5–16).
Conclusion – DBS in STN improves balance performance in patients with severe PD.