Postural Sway Measurement Using a Body-Worn Movement Sensor in Clinical Stroke Rehabilitation: Exploring Sensitivity to Change and Responsiveness

Abstract

Importance: During rehabilitation, the balance of a person with stroke is commonly monitored using the Berg Balance Scale and the Mini-Balance Evaluation Systems Test. These tests evaluate the ability to maintain balance in an upright position while performing tasks. Currently, clinical practice lacks an adequate assessment of balance impairments like the increased postural sway poststroke. Integrating postural sway measurement with a body-worn inertial measurement unit could offer clinicians an objective and rapid measurement method. Objective: Sensitivity to change and responsiveness of postural sway measurement during stroke rehabilitation were explored. Design: A longitudinal study was conducted. Setting: Data were collected in 5 rehabilitation centers. Participants: 94 people with stroke were included in the study. Intervention: Sensitivity to change was evaluated by comparing the percentages of participants who exceeded the minimal detectable change for both the conventional and inertial measurement unit tests. Responsiveness was assessed through hypotheses testing, utilizing both a criterion approach (external criterion: a 5-point retrospective Global Rating of Change score) and a construct approach. Results: At discharge, only 3.2% to 23.9% of the participants showed genuine improvement (ie, had a lower postural sway) on the inertial measurement unit test, compared to 33% to 60% on the conventional tests. In total, 67.4% of the hypotheses were rejected. Conclusions: The sensitivity to change and responsiveness of postural sway measurement in people with stroke are limited. Restoring balance to achieve functional independence is not necessarily dependent on, or associated with, the level of postural sway. At present, integrating postural sway measurement into clinical stroke rehabilitation seems to provide no added value for monitoring balance. Relevance: A novel approach to balance assessment in clinical stroke rehabilitation was investigated. It was found that while most participants improved in terms of functionality and independence, only a small percentage exhibited a significant change in postural sway. Therefore, postural sway may not effectively serve as an indicator of improved movement quality. This insight is crucial for both researchers and clinicians involved in neurorehabilitation.