Background: The effect of subthalamic deep brain stimulation on balance in Parkinson's disease remains unclear.
Objective: To evaluate the effect of subthalamic nucleus stimulation on balance in Parkinson's disease using posturography.
Methods: 16 patients (9 women) who underwent subthalamic deep brain stimulation [mean age 59.6 years (46-70); mean disease duration 15.6 years (7-25); mean duration of subthalamic stimulation 32.1 months (3.0-69.6)] and 13 healthy age-matched controls were evaluated using a static posturography analysis. Patients were assessed under four conditions: 1) off medication/off stimulation; 2) off medication/on stimulation; 3) on medication/off stimulation and 4) on medication/on stimulation in ten experimental paradigms, some reproducing common situations of daily living. The displacement of the centre of pressure was analyzed using 14 posturographic parameters. The Mann-Whitney test was used to compare patients with controls. The Wilcoxon signed rank test was used to compare patients under different clinical conditions.
Results: Patients off medication/off stimulation showed larger and more rapid displacements of the centre of pressure than controls in most paradigms (p<0.05), particularly when performing a dual task. Subthalamic stimulation alone reduced the lateral excursion and anterior-posterior velocity of the centre of pressure in quite stance paradigms (p<0.05). Subthalamic stimulation combined with antiparkinsonian medication did not induce statistically significant changes in posturagraphic measures in any experimental paradigm.
Conclusions: Although subthalamic stimulation alone may induce some positive effect on balance, subthalamic stimulation in addition to antiparkinsonian medication, which is the usual treatment in clinical practice, did not modify balance as assessed by static posturography in patients with Parkinson's disease.
Keywords: Balance; Deep brain stimulation; Posturography; Subthalamic nucleus.
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