Balance-Based Torso-Weighting
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Introduction[edit | edit source]
Balance-based torso-weighting (BBTW) is a treatment method for people with ataxia or balance loss.
Description[edit | edit source]
In people with ataxia, uncoordinated movement can result in postural instability and falls[1][2]. 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[3].
Method[edit | edit source]
BBTW is an assessment and treatment method for directional instability and loss of balance. It can be summed up in 5 steps:
- Assess balance and posture in standing, transitional movements, and response to trunk perturbations in different directions
- Identify direction of sway or balance loss
- Place small amounts of weight on the torso, using a vest, to counter loss of balance control
- Reassess balance and posture
- Repeat steps 1-4 as necessary
Assess balance and posture in standing, transitional movements, and response to trunk perturbations in different directions
The clinician strategically places light weights (objects with designated mass) on the trunk to counter instability. The mechanism for the effectiveness of BBTW is not specifically known. Prior work has disproven a strictly biomechanical mechanism (Crittendon et al., 2014) and argued against alternative hypotheses such as joint compression or increased conscious awareness proposed when heavier weights are used (Hunt, Widener, & Allen, 2014). The mechanism likely involves enhanced sensory input to improve perception of self-motion and position (Crittendon et al., 2014). The theoretical rationale for proposing BBTW for people with CA is that a stronger sensory signal may help compensate for sensory integration deficits resulting in ataxia and postural control issues in this population.
The therapist started balance assessment by observing the relative amount and direction of sway while the participant stood quietly (Gibson-Horn, 2008). The therapist then applied anterior, posterior, and lateral perturbations (nudges) at the shoulders and pelvis to observe the participant's response and direction of balance loss. Rotational forces were applied manually through the shoulders and pelvis to determine asymmetries in the participant's ability to maximally resist while maintaining upright balance.
Loss of balance during perturbations and rotational forces was scored on a 0–4 scale developed to facilitate application of weights in the BBTW procedure (Allen et al., 2018). Responses were scored: (0) No balance loss, brisk response to perturbation; (1) Minimal balance loss, delayed onset of return to upright, (2) Moderate balance loss, large trunk movement or parachute reaction with no foot movement; (3) Moderate–severe balance loss, large trunk movement with foot movement or takes a small step; (4) Severe balance loss, manual contact by the researcher required to prevent a fall. The scale has shown good to excellent inter-rater agreement (Allen et al., 2018) indicating that other therapists can observe balance loss similarly.
Evidence[edit | edit source]
Balance-based torso-weighting has mainly been used in the patients with multiple sclerosis population[4][5], 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[4].
References[edit | edit source]
- ↑ 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. 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 impairments. Neuropathology and applied neurobiology. 2008 Apr;34(2):155-68.
- ↑ 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.
- ↑ 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.
- ↑ 4.0 4.1 Crittendon A, O'Neill D, Widener GL, Allen DD. Standing data disproves biomechanical mechanism for balance-based torso-weighting. Archives of physical medicine and rehabilitation. 2014 Jan 1;95(1):43-9.
- ↑ 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.
