Jump to content

Balance-Based Torso-Weighting

Original Editor - Jonathan Wong Top Contributors - Jonathan Wong, Kim Jackson, Khloud Shreif and Nehal Shah

Introduction

Balance-based torso-weighting (BBTW) is a treatment method for people with ataxia or balance loss. It has been trialled as well for community-dwelling older adults[1].

Description

In people with ataxia, uncoordinated movement can result in postural instability and falls[2][3]. Postural instability may manifest as increased variability of direction and amplitude of movement, particularly at the trunk, which increases fall risk for people with ataxia[4].

BBTW makes use of external body weights to improve mobility and balance, typically in patients with multiple sclerosis or cerebellar ataxia. BBTW shows immediate improvements in balance and walking[5][6].

[7]The above video demonstrates the use of a weighted vest that shows improvements in walking for a person with multiple sclerosis.

Method[3][5][6][8][9][10][11]

A Balance-based torso-weighting protocol has been proposed in the literature[8], which has been adopted and expanded on in many studies after[5][6] [9] [3][10][11] .

BBTW can currently be summed up as a 5 part intervention:

  1. Assessment of balance and alignment in standing, transitional movements, and in response to multidirectional trunk perturbations
  2. Identification of the direction of sway or balance loss
  3. Placement of small amounts of weight on the torso to counter loss of balance control
  4. Reassess abnormalities in balance and alignment found from initial assessment
  5. Repeat process as needed

1. Assessment of balance and alignment in standing, transitional movements, and in response to multidirectional trunk perturbations

  • Observe body sway while subject stands with feet together, eyes open then eyes closed, without the vest.
  • Observe the subject's reaction to perturbation with nudges to the upper torso in 4 directions, with another person guarding the subject from behind
    • Posterior perturbation involved gently applying a posterior force at the sternum
    • anterior perturbation involved an anterior force applied at about T4 and 5,
    • lateral perturbation involved a force from each side at the shoulder.
    • If the upper torso was stable, perturbations were performed at the hips in a similar manner.
  • Observe trunk rotation from resistance applied to the shoulders in a diagonal direction (right anterior, left posterior and left anterior, right posterior).

2. Identification of the direction of sway or balance loss

  • Note the latency, amount of body sway or loss of balance, and directions of occurrence[9]
  • Balance loss can be defined as tilt of the trunk that requires a step response, or manual contact by a researcher to regain balance[10]
  • The identified direction of sway and instability observed from step 1 determines initial weight placement

3. Placement of small amounts of weight on the torso to counter the loss of balance control

  • Small weights in 0.11kg (.25lb) to 0.23kg (.5lb) increments (up to a maximum of 1.13kg [2.5lb] for any 1 subject) are placed in or on the vest to counter the identified direction(s) of instability
  • Weights could be placed in pockets or attached with Velcro on the neoprene vest, medial to lateral from the shoulders to the waist.
  • Generally, 2 types of weighting were employed: opposite to the direction of balance loss or the same direction as the balance loss.

4. Reassess abnormalities in balance and alignment found from initial assessment

  • Weighting is finalised by asking subjects to:
    • walk and turn,
    • get up and down from a chair
  • The therapist looks for greater stability with perturbations, and improved function and ability to resist rotation.
  • Perturbations are repeated, and weights moved or added until the participant shows a reduction in directional balance loss or increase in symmetrical resistance to rotational forces.

Proposed mechanisms of action

Three mechanisms behind BBTW have been proposed, as listed below:

  1. Joint compression
    • Weights help with joint compression, increasing sensory input which facilitates cocontraction of the muscles and thus increases stability[12]
  2. Changing center of mass
    • An altered center of mass may change the moment of inertia and thus affect movement[13][14]
  3. Improving awareness
    • Weights enhance sensory input and thus improve awareness of the weighted body part[15]

The mechanism of effect for BBTW still remains unknown, although it is believed that BBTW does not change centre of mass since people do not mechanically shift in the direction of weighting[16]. From the same study, many participants stated forgetting they had the weights on or not feeling them after a while, even during a short session of one to two hours. Therefore increased attention does not seem a likely mechanism of effect for BBTW.

Evidence

Balance-based torso-weighting has mainly been used in the patients with multiple sclerosis population[16][9], however, there is a shifting trend in that this treatment method has been adapted for patients with cerebellar ataxia as well.

  • BBTW has shown improvements for people with multiple sclerosis in gait velocity and cadence, and static standing[16]
  • Placing weights on the waist or distal extremities of 14 subjects with cerebellar ataxia improved gait velocity in 68% of subjects, and the effectiveness of weights on ataxic limbs does not seem to diminish over time[13]
  • Shoulder weighting reduced lateral sway in 10 persons with cerebellar ataxia[17], and static stability but not gait speed increased for people with cerebellar ataxia[3]
  • After BBTW, people with multiple sclerosis have immediate improvements in static stability, showing decreased lateral sway when standing with eyes open and closed, and optimised variability of postural sway, as well as increased ability to resist rotational forces while standing [5][6][16] [11]
  • BBTW has resulted in improved dynamic stability in sit-to-stand transfers, and walking: showing improvements in gait speed, cadence, and percentage of gait cycle in single-limb support in people with MS[8] [6][9]
  • BBTW results in a clinically significant reduction in the number of falls (35%) in the MS population[10]
  • BBTW - donning a weighted vest for 2 hours, twice per day for 4 months, results in improvements in measures of gait, balance, chair stands, fall risk, and mobility disability in a group of older, mobility-impaired adults even 8 hours after removal of vest[1]

Despite the evidence showing significant and positive effects on balance, only one study has mentioned a sustained improvement in balance after removal of the vest.

References

  1. ↑ 1.0 1.1 Noah, Sean BA1; Gibson-Horn, Cynthia PT, BS2; Vincenzo, Jennifer L. PT, PhD3. Four Months of Wearing a Balance Orthotic Improves Measures of Balance and Mobility Among a Cohort of Community-Living Older Adults. Journal of Geriatric Physical Therapy 42(4):p 216-223, October/December 2019. | DOI: 10.1519/JPT.0000000000000174
  2. ↑ Rüb U, Brunt ER, Seidel K, Gierga K, Mooy CM, Kettner M, Van Broeckhoven C, Bechmann I, La Spada AR, Schöls L, Den Dunnen W.S Spinocerebellar ataxia type 7 (SCA7): widespread brain damage in an adult-onset patient with progressive visual impairments in comparison with an adult-onset patient without visual impairmentsNeuropathology and applied neurobiology. 2008 Apr
  3. ↑ 3.0 3.1 3.2 3.3 Widener GL, Conley N, Whiteford S, Gee J, Harrell A, Gibson‐Horn C, et al. Changes in standing stability with balance‐based torso‐weighting with cerebellar ataxia: A pilot study. Physiotherapy research international : the journal for researchers and clinicians in physical therapy. 2020;25(1):e1814–n/a.
  4. ↑ Conte C, Pierelli F, Casali C, Ranavolo A, Draicchio F, Martino G, Harfoush M, Padua L, Coppola G, Sandrini G, Serrao M. Upper body kinematics in patients with cerebellar ataxia. The Cerebellum. 2014 Dec;13:689-97.
  5. ↑ 5.0 5.1 5.2 5.3 Widener GL, Allen DD, Gibson-Horn C. Balance-based torso-weighting may enhance balance in persons with multiple sclerosis: preliminary evidence. Arch Phys Med Rehabil. 2009 Apr;90(4):602-9. doi: 10.1016/j.apmr.2008.10.027. PMID: 19345775.
  6. ↑ 6.0 6.1 6.2 6.3 6.4 Widener GL, Allen DD, Gibson-Horn C. Randomized clinical trial of balance-based torso weighting for improving upright mobility in people with multiple sclerosis. Neurorehabil Neural Repair. 2009 Oct;23(8):784-91. doi: 10.1177/1545968309336146. Epub 2009 May 26. PMID: 19470807.
  7. ↑ WTNH News8. Customized weighted vest could help with balance issues. Available from: http://www.youtube.com/watch?v=yNr-czGTuwg
  8. ↑ 8.0 8.1 8.2 Gibson-Horn C. Balance-based torso-weighting in a patient with ataxia and multiple sclerosis: a case report. J Neurol Phys Ther. 2008 Sep;32(3):139-46. doi: 10.1097/NPT.0b013e318185558f. PMID: 18978670.
  9. ↑ 9.0 9.1 9.2 9.3 9.4 Gorgas AM, Widener GL, Gibson‐Horn C, Allen DD. Gait changes with balance‐based torso‐weighting in people with multiple sclerosis. Physiotherapy Research International. 2015 Mar;20(1):45-53.
  10. ↑ 10.0 10.1 10.2 10.3 Horn KK, Allen DD, Gibson-Horn C, Widener GL. Effects of Torso-Weighting on Standing Balance and Falls During the Sensory Organization Test in People with Multiple Sclerosis. Int J MS Care. 2018 Mar-Apr;20(2):68-75. doi: 10.7224/1537-2073.2015-090. PMID: 29681777; PMCID: PMC5898918.
  11. ↑ 11.0 11.1 11.2 Hunt CM, Widener G, Allen DD. Variability in postural control with and without balance-based torso- weighting in people with multiple sclerosis and healthy controls. Phys Ther. 2014 Oct;94(10):1489-98. doi: 10.2522/ptj.20130288. Epub 2014 Jun 5. PMID: 24903118; PMCID: PMC4183891.
  12. ↑ Goff B. The application of recent advances in neurophysiology to Miss M. Rood's concept of neuromuscular facilitation. Physiotherapy. 1972 Dec 10;58(12):409-15. PMID: 4668364.
  13. ↑ 13.0 13.1 Morgan, M. H. (1975). Ataxia and weights. Physiotherapy, 61(11), 332-334.
  14. ↑ Bernstein N. The Coordination and Regulation of Movement. London: Pergamon Press; 1967.
  15. ↑ Gordon H. (1939). The Cerebellum Of Man, Brain, Volume 62, Issue 1, March 1939, Pages 1–30.
  16. ↑ 16.0 16.1 16.2 16.3 Crittendon A, O'Neill D, Widener GL, Allen DD. Standing data disproves biomechanical mechanism for balance-based torso-weighting. Arch Phys Med Rehabil. 2014 Jan;95(1):43-9. doi: 10.1016/j.apmr.2013.08.235. Epub 2013 Aug 31. PMID: 24001445; PMCID: PMC3918424.
  17. ↑ Lucy SD, Hayes KC. Postural sway profiles: normal subjects and subjects with cerebellar ataxia. Physiother Can. 1985;37(37):140-8.
Retrieved from "https://www.physio-pedia.com/w/index.php?title=Balance-Based_Torso-Weighting&oldid=358269"