The validity, reliability, and sensitivity of a smartphone-based seated postural control assessment in wheelchair users
Seated postural control is essential for wheelchair users to maintain proper position while performing activities of daily living. Clinical tests are commonly used to measure seated postural control in wheelchair users, yet they are subjective and lack sensitivity. Lab-based measures are highly sensitive but are limited in scope and restricted to research settings. Establishing a valid, reliable and accessible measurement tool of seated postural control is necessary to better understand and remotely track seated postural control. Therefore, the purpose of this study was to examine the validity, reliability, and sensitivity of smartphone-based postural control assessments in wheelchair users. Eleven participants (age: 35.4 ± 17.9) completed two experimental visits 1-week apart consisting of three clinical tests: Trunk Control Test (TCT), Function in Sitting Test (FIST), and Tee-Shirt Test, as well as, standardized instrumented balance tasks that manipulated vision (eyes open and closed), and trunk movement (functional reach and stability boundary). During these balance tasks, participants held a smartphone and research-grade accelerometer to their chest. Maximum and root mean square (RMS) acceleration in the medial-lateral (ML) and anterior-posterior (AP) axes were derived. Participants were grouped into non-impaired and impaired postural groups based on FIST scores. Spearman rank-order correlations between the two devices’ outcome measurements were conducted, and receiver operating characteristic (ROC) and the area under the curves (AUC) were determined to distinguish participants with and without impaired postural control. The reliability of outcome variables was assessed using inter-class correlations. Strong correlations between outputs derived from the smartphone and research-grade accelerometer were seen across balance tasks (ρ=-0.75–1.00; p≤0.01). The AUC for ROC plots were significant for RMS ML sway during the eyes open task and functional stability boundary (p=0.05 and 0.02, respectively). Reliability of smartphone accelerometry was comparable to the research-grade accelerometer and clinical tests. This pilot study illustrated that smartphone technology may be able to provide a valid and reliable assessment of seated postural control and have the ability to distinguish between those with and without impaired postural control. Leveraging this form of technology could allow for remote, accessible and objective seated postural control assessments for wheelchair users.
seated postural control, smartphone technology, wheelchair users, clinical tests, measurement tool.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign