Balance deficits are among the most impairing symptoms in people with Parkinson’s disease, and impacts mobility, quality of life and ultimately independence. In order to inform clinicians of the need for rehabilitation and evaluation of its effectiveness, it is essential to investigate the robustness of prevailing balance assessment tools in people with Parkinson’s disease under circumstances similar to clinical practice and by presenting the clinically relevant measurement error. The Mini-BESTest entails 4 subcomponents: anticipatory postural adjustments, postural responses, sensory orientation and dynamic gait. These items are highly relevant for balance in people with Parkinson’s disease. However, its robustness between test administrators and at different time points has only presented as relative values that are highly dependent on the diversity in the sample and are difficult to translate into clinical practice. The aim of this study was therefore to investigate the measurement error of the Mini-Bestest in people with Parkinson’s disease, when assessed by two different test administrators and at different time points.
Twenty-seven people with Parkinson’s disease were assessed with the Mini-BESTest by one experienced and one inexperienced physiotherapist. The assessments took place in different treatment rooms at a hospital in random order. One week later, the experienced physiotherapist reassessed all participants at the same time of day. The results between the physiotherapists showed a measurement error of 4.1 points for the total score of the Mini-BESTest (accounting for 15% of the total score of the test). A systematic error between the testers showed that the experienced physiotherapist rated the people with Parkinson’s disease lower than the inexperienced physiotherapist. Postural responses had the highest proportional error (38% of the score available) whereas sensory orientation had the lowest (17%). The results for the assessments by the experienced physiotherapist, 7 days apart, showed a measurement error of 3.4 points for the Mini-BESTest´s total score (12% of the total score of the test). Postural responses had the highest measurement error (27% of the score available) whereas sensory orientation had the lowest error (13%).
Our results show that in spite of entailing unique and clinically relevant items such as postural responses, turning and dual-task interference, the Mini-BESTest´s measurement error was similar to that of other less sensitive balance tests. Nevertheless, the results stress the importance of thorough theoretical and practical training before using the test, particularly when assessing postural responses. Moreover, clinicians need to be aware of the measurement error when interpreting the outcomes of rehabilitation.
Figure: Clinical balance assessment in action
Löfgren, N., Lenholm, E., Conradsson, D., Ståhle, A., & Franzén, E. (2014). The Mini-BESTest-a clinically reproducible tool for balance evaluations in mild to moderate Parkinson’s disease? BMC neurology, 14(1), 235. https://doi.org/10.1186/s12883-014-0235-7