Evaluation of postural balance control in patients with multiple sclerosis - effect of different sensory conditions and arithmetic task execution. A pilot study.

ABSTRACT

BACKGROUND AND PURPOSE: The purpose of this study was to investigate the effect of concomitant cognitive task execution and different sensory conditions on balance control in patients with multiple sclerosis (MS). MATERIAL AND METHODS: Thirty-two subjects with MS and 30 healthy age- and sex-matched control subjects were included in the study. Balance Performance Oriented Mobility Assessment was performed in all subjects. Their spontaneous sway characteristics while standing with different sensory conditions and during execution of a simple arithmetic task were analysed. Mean sway in the coronary and sagittal plane, as well as sway velocity, were measured. RESULTS: The values of all evaluated variables obtained in all tests were significantly higher in the MS group than in controls. In the MS group, more pronounced progression of changes in response to increased difficulty of the test was also observed. Analysis of risk of falls in MS revealed a significant increase of sway velocity and mean sway in the mediolateral and anteroposterior plane in the majority of tests. CONCLUSIONS: Postural stability in patients with MS is significantly decreased in comparison with the control group in all evaluated conditions. Stability deficit is enhanced in response to more difficult conditions of evaluation. Increased risk of falls is related to the increased postural sway velocity and length of mean sway; this association is most pronounced in the coronary plane.