Validity of the Sock Test for Sitting Balance: A Functional Sitting Balance Assessment

PURPOSE: Balance is a foundation for function as, “The ability to control our body’s position in space is fundamental to everything we do” (Shumway-Cook & Woollacott, 2007, p.158). The importance of sitting balance has been established with several studies strongly correlating sitting balance to self-care functioning (Gorman et al., 2014). However, no universally accepted method of assessing or describing a patient’s sitting balance has been identified (Sibley, Beauchamp, Van Ooteghem, Straus, & Jaglal, 2015), and current standardized sitting balance assessments are not grounded in an occupation-based approach of assessing the ‘whole person’. The Sock Test for Sitting Balance (STSB), developed using the theory of Occupational Adaptation and the Systems Framework of Postural Control, has the potential to be an effective and efficient measure of sitting balance and function, but had not been compared to a validated balance tool and had not been tested to see if it could differentiate between a healthy versus hospitalized population.

The aim of this study was to determine if the STSB is a valid assessment of sitting balance for use by occupational therapists in the acute care setting.

DESIGN: This descriptive study is a non-randomized, cross-sectional design utilizing purposeful sampling and case matching.

METHODS: Case-matching was utilized to match 21 hospitalized participants to 21 apparently healthy individuals. Concurrent validity of the STSB was then investigated by correlating the sitting balance results obtained on the STSB to those of the “Adapted Functional Reach” (AFR) assessment (Thompson & Medley, 2007), the Functional Independence Measure (FIM^TM) Chair Transfer subscale, and to the Kansas University Sitting Balance Scale (KUSBS). Non-parametric data analyses Spearman’s rho and Mann-Whitney U were used to answer the research questions due to lack of normality in the data.

RESULTS: There is a significant relationship between STSB results and Adapted Functional Reach-Forward results (r _s (40) = -.382, p = .012) for all participants but not for the hospitalized cohort alone (r _s (19) = -.178, p = .440). Validity was established with a significant relationship between ranked STSB results and ranked level of independence on the FIM^TM bed-chair transfer subscale (r _s (19) = -.677, p = .001), and to levels of sitting balance on the KUSBS (, r _s (19) = -.614, p = .003.). The results of the study also showed that the STSB can differentiate between a hospitalized population and an apparently healthy population (z = 2.377, p = .017, r = .37).

CONCLUSION: This study advances the use of the task of sock donning and doffing as a sitting balance measurement tool, helping establish the STSB for use by occupational therapists in the acute care setting. Observation of performance yields information on the components of the Systems Framework of Postural Control and is an appropriate task in which to assess a patient’s level of adaptive behavior per Occupational Adaptation.

IMPACT STATEMENT: The proposed sitting balance assessment tool is an occupation-based, top-down instrument that has good clinical utility in the acute care setting. Though further research is needed to improve utility of results (i.e. cut-off scores, normative data by age), the results of this study confirm its ability to be implemented in practice. As sitting balance is a powerful predictor of future function, the use of a standardized balance assessment tool in the acute care setting is indicated as one piece upon which occupational therapists can base their discharge recommendations.

References

Gorman, S.L., Harro, C.C., Platko, C., & Greenwald, C. (2014). Examining the function in sitting test for validity, responsiveness, and minimal clinically important difference in inpatient rehabilitation. Archives of Physical Medicine and Rehabilitation, 95(12), 2304- 2311. https://doi.org/10.1016/j.apmr.2014.07.415

Shumway-Cook, A. & Woollacott, M.H. (2007). Normal postural control. Motor control: Theory and practical applications (3rd ed.)(pp.163-191). New York: Lippincott Williams & Wilkins.

Sibley, K.M., Beauchamp, M.K., Van Ooteghem, K., Straus, S.E., & Jaglal, S.B. (2015). Using the systems framework for postural control to analyze the components of balance evaluated in standardized balance measures: a scoping review. Archives of Physical Medicine and Rehabilitation, 96, 122-32. https://doi.org/10.1016/j.apmr.2014.06.021

Thompson, M. & Medley, A. (2007). Forward and lateral sitting functional reach in younger, middle-aged, and older adults. Journal of Geriatric Physical Therapy,30(2), 43- 48. Retrieved from https://ovidsp.tx.ovid.com/sp3.29.1a/ovidweb.cgi?&S=AMCGFPNNNODDMAMLNCFKBFJCDGOFAA00&Link+Set=S.sh.22%7c1%7csl_10