ORIGINAL ARTICLE The Assessment of Postural Control With Stochastic Resonance Electrical Stimulation and a Neoprene Knee Sleeve in the Osteoarthritic Knee Amber T. Collins, PhD, J. Troy Blackburn, PhD, Chris W. Olcott, MD, Joanne M. Jordan, MD, MPH, Bing Yu, PhD, Paul S. Weinhold, PhD ABSTRACT. Collins AT, Blackburn JT, Olcott CW, Jordan JM, Yu B, Weinhold PS. The assessment of postural control with stochastic resonance electrical stimulation and a neoprene knee sleeve in the osteoarthritic knee. Arch Phys Med Rehabil 2012;93:1123-8. Objective: To determine whether the combination of stochas- tic resonance (SR) electrical stimulation and a neoprene knee sleeve could improve center of pressure (COP) measures of postural sway during single-leg stance in those with knee osteoarthritis (OA). Design: Counterbalanced, repeated-measures intervention study of osteoarthritic adults during 6 different testing condi- tions: a control condition— control 1 (1); a counterbalance sequence of 4 treatment conditions—no stimulation with sleeve (2), 75% stimulation with sleeve (3), 100% stimulation with sleeve (4), and 150% stimulation with sleeve (5); and a second control condition— control 2 (6). Setting: University sports medicine research laboratory. Participants: Subjects (N=52) with radiographically deter- mined, minimal-to-moderate medial knee OA. Interventions: Neoprene knee sleeve and SR electrical stimulation. Main Outcome Measures: COP displacement in the medial- lateral and anterior-posterior directions was collected to resolve the mean velocity, SD, range, and total path length. Results: No significant differences were found in the study measures between the testing conditions. Additionally, no sig- nificant differences were found between the 3 stimulation con- ditions or between the sleeve-alone and stimulation conditions for any of the study measures. Conclusions: There were no significant improvements in bal- ance with the use of a neoprene knee sleeve. Additionally, there was no added benefit of the SR stimulation as applied in the current configuration in this population. Key Words: Braces; Knee; Electric stimulation; Osteoar- thritis; Rehabilitation. © 2012 by the American Congress of Rehabilitation Medicine O STEOARTHRITIS (OA) is a debilitating disease and is especially common in the elderly, affecting roughly 10% of those older than 65 years. 1 Abnormal postural control 2 beyond that attributable to aging effects, as well as knee instability, 3 has been demonstrated in those with knee OA and may put this population at greater risk of falling. Postural control is a reflection of sensory input (including propriocep- tion), central processing, neuromuscular responses, and lower limb muscle strength. The abnormal postural control associated with knee OA may be a direct result of proprioceptive deficits, which are also known to exist in this population and exceed those of general aging effects. 4-7 Age has been demonstrated to have a detrimental effect on balance, 8,9 but this may be com- pounded in knee OA by the further impairment in propriocep- tion. By improving proprioception, it is possible that balance itself may be improved. Birmingham et al 10 demonstrated improvements in proprioception with the use of a valgus- producing brace in those with knee OA during a non–weight- bearing joint position sense task. A more recent study 11 dem- onstrated that a neoprene knee sleeve produced a significant improvement in joint position sense in those with knee OA during a partial weight-bearing task. Improvements in sensory input (specifically proprioception) may translate into improve- ments in balance, which may result in a reduction in the risk of falls in those with knee OA who are elderly and are more susceptible to falling compared with a younger population without knee OA. However, the effect of wearing a knee sleeve or brace on the control of balance of individuals with knee OA is limited to a few studies 10,12,13 with conflicting results. Chuang et al 12 dem- onstrated improvements in both static and dynamic balance with the use of a neoprene knee sleeve, and Hassan et al 13 showed significant reductions in postural sway with a loose elastic bandage. Conversely, Birmingham 10 did not see a sig- nificant effect on balance with the use of a valgus-producing brace. Based on the conflicting results in the current literature, it is unclear whether postural control can be affected with the use of a knee sleeve. Stochastic resonance (SR) stimulation has been investigated as a tool for improving postural control in a variety of diseased From the Departments of Biomedical Engineering (Collins, Yu, Weinhold), Or- thopaedics (Blackburn, Olcott, Yu, Weinhold), and Exercise and Sport Science (Blackburn), the Center for Human Movement Science, Division of Physical Therapy (Yu), and the Thurston Arthritis Center (Jordan), University of North Carolina, Chapel Hill, NC. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organi- zation with which the authors are associated. Reprint requests to Amber T. Collins, PhD, 126 Spencer Lab, University of Delaware, Newark, DE 19711, e-mail: atcollin@udel.edu. In-press corrected proof published online on Mar 17, 2012, at www.archives-pmr.org. 0003-9993/12/9307-00894$36.00/0 doi:10.1016/j.apmr.2011.12.006 List of Abbreviations ANOVA analysis of variance AP anterior-posterior COP center of pressure ML medial-lateral OA osteoarthritis SR stochastic resonance WOMAC Western Ontario and McMaster Universities Osteoarthritis Index 1123 Arch Phys Med Rehabil Vol 93, July 2012