Measuring standing balance in multiple sclerosis: Further progress towards an automatic and reliable method in clinical practice

Abstract

Balance deficits in multiple sclerosis (MS) are often monitored by means of observer-rated tests. These may provide reliable data, but may also be time-consuming, subject to inter-rater variability, and potentially insensitive to mild fluctuations throughout the clinical course. On the other hand, laboratory assessments are often not available. The Nintendo Wii Balance Board (WBB) may represent a low-cost solution. The purpose of the current study was to examine the methodological quality of WBB data in MS (internal consistency, test-retest reliability), convergent validity with observer-rated tests (Berg Balance Scale, BBS; Timed- Up and Go Test, TUG), and discriminative validity concerning clinical status (Expanded Disability Status Scale, EDSS). Methods: Standing balance was assessed with the WBB for four minutes in 63 MS patients at two assessment points, four months apart. Additionally, patients were examined with the BBS, TUG and the EDSS. Results: A period of four minutes on the WBB provided data characterized by excellent internal consistency and test-retest reliability. Significant correlations between WBB data and results of the BBS and TUG were obtained after merely two minutes on the board. An EDSS mediansplit revealed that higher EDSS values (>3) were associated with significantly increased postural sway on the WBB. Conclusions: WBB measures reflecting postural sway are methodologically robust in MS, involving excellent internal consistency and test-retest reliability. They are also characterized by convergent validity with other considerably lengthier observer-rated balance measures (BBS) and sensitive to broader clinical characteristics (EDSS). The WBB may hence represent an effective, easy-to-use monitoring tool for MS patients in clinical practice.