● Up to 85% of people with multiple sclerosis (PwMS) experience balance and walking impairments related to sensory loss, muscle weakness, ataxia, or spasticity.

● Walking impairments can cause frequent falls and limitations in activities and participation in daily life.1

● Evidence suggests that sensori-motor control is a crucial parameter for maintaining stability.

● Balance-Based Torso-Weighting® (BBTW), a non-pharmaceutical intervention in which patients wear light weights on the trunk, has resulted in immediate functional improvements in PwMS, including increased gait speed.2-4

● The purpose of this study was to examine center of pressure changes during quiet standing with and without BBTW.

Methods

Discussion

Center of Pressure Changes During Quiet Standing with and without Balance-Based Torso Weighting in People with Multiple Sclerosis

Diane D. Allen1, Gail L. Widener2, Cynthia Gibson-Horn2*1Graduate Program in Physical Therapy UCSF/SFSU, 2Physical Therapy Department Samuel Merritt University

● Data collection and analysisCenter of pressure in medial-lateral (x) and

anterior-posterior (y) directions at 600 Hz using BioWare software.

● Some people showed distinct decreases in range of center of pressure with weighting, but not everybody. The only condition that was statistically significant between non-weighted and weighted conditions was eyes closed, anterior-posterior direction, people with MS but lower disability (EDSS 2-4).● Limitations included large standard deviation across this small sample of participants, particularly in eyes closed conditions and people with more disability. ● Like in a prior study by Huisinga et al.5 quiet standing was significantly different between people with MS and healthy controls for root mean square and approximate entropy (p<.001). Lyapunov exponent was only different between healthy controls and people with greater disability from MS (EDSS 4.5-6) in the eyes open medial-lateral direction. Unlike the prior study, range of center of pressure values was greater in people with MS than healthy controls for all conditions.● The classification of low vs. high disability in people with MS based on EDSS score may not have captured the best responders to the BBTW intervention.

Introduction

Acknowledgement: This study was supported by Award Number R15HD066397 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Eunice Kennedy Shriver National Institutes of Child Health and Human Development or the National Institutes of Health.

*Cynthia Gibson-Horn has part ownership of Motion Therapeutics which manufactures and sells BBTW garments.

References•Cromwell, R.L., and Newton, R.A. Relationship between balance and gait stability in healthy older adults. J Aging Phys Activity. 2004;11: 90-100.•Gibson-Horn, C. Balance-Based Torso Weighting in a person with ataxia and multiple sclerosis: A case report. J Neurol Phys Ther. 2008;32:139-146.•Widener, G.L., Allen, D.D., and Gibson-Horn, C. Balanced-Based Torso-Weighting may enhance balance in persons with multiple sclerosis: Preliminary evidence. Arch Phys Med Rehabil. 2009;90:602-609.•Widener, G.L., Allen, D.D., and Gibson-Horn, C. Randomized clinical trial of Balance-Based Torso Weighting for improving upright mobility in people with multiple sclerosis. Neurorehabil Neural Repair. 2009;23:784-791.•Huisinga, J.M., Yentes, J.M., Filipi, M.L., and Stergiou, N. Postural control strategy during standing is altered in patients with multiple sclerosis. Neuroscience Letters. 2012;524:124-128.•Cattaneo, D., and Jonsdottir, J. Sensory impairment in quiet standing in subjects with multiple sclerosis. Mult. Scler. 2009;15:59-67.

Results

● 31 female volunteers: 20 with MS, 11 controls

*Matched to people with MS by age, height, weight. Recruitment continues. MS = multiple sclerosis, SD = standard deviation, EDSS = Expanded Disability Status Scale

●Informed consent●Physician approval, documented MS dx●Medical questionnaire

●Recent fall history●MS symptoms experienced

●Quiet standing trials on Kistler forceplate●With torso garment but no weights, participants stood

on a forceplate as still as possible for 10 seconds with eyes open then 10 seconds with eyes closed

●Participants underwent BBTW protocol2-4 to determine placement of light weights (<1.5% body weight) on the garment.

●With weights on, (0.75-2.75 pounds) participants repeated the quiet standing trials on the forceplate.

Conclusion

Figure 1. BBTWTM

Garment and Weights

● The linear measures of range and root mean square looked similar. Medial-lateral excursion was larger than anterior-posterior excursion for both range and root mean square (p<.05). Excursion for eyes closed conditions was larger than eyes opened (p<.05). MS participants had larger excursions and standard deviations than healthy controls (p<.001).

● The non-linear measures indicated more variability over time in healthy controls, and more rigidly controlled sway in people with MS.

 

 

People with MS (n=20)

Healthy controls* (n=11)

Age in years, mean (SD), range

49.35 (13.35), 25-68 51.5 (11.68), 29-69

Years with diagnosis, mean (SD)

12.8 (8.2)

EDSS score equivalent 4.1 (1.6), 2-6

Number (%) claiming falls in the past 6 months

11 (55%) 2 (16%)

Participants with multiple sclerosis show differences from healthy controls in center of pressure during quiet standing using linear and non-linear measures. Eyes open or closed conditions, and anterior-posterior versus medial-lateral directions also differ. Weighting made a difference for some participants, but reached statistical significance in only one condition. Additional study is warranted to determine which participants respond best to BBTW.

Figure 2. Sample Weight Placement on

Garment (3 half-pound weights) Mean Range Center of Pressure

Medial-Lateral Direction

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● The only statistically significant difference between non-weighted and weighted conditions was in the range of people with low disability (EDSS = 2-4) in the eyes closed anterior-posterior direction.

● Some participants showed changes in center of pressure with weighting. Graphs show healthy control matched with participant with MS.

● Dependent variablesLinear measures of range and root mean square;

non-linear measures of approximate entropy and Lyapunov exponent. Data were downsampled to 25Hz for root mean square and non-linear statistics.

● Statistical Analyses (alpha set at .05)• Paired t-tests to compare means for each variable within groups.• Independent t-tests to compare differences for each variable between groups.

Healthy Control - EO

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With Weight

Mean Approximate Entropy Medial-Lateral Direction

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