Changes in Standing Stability with Balance-Based Torso-Weighting in People with Cerebellar Ataxia: a Pilot Study.

Research Report
Population: Adult

Gail L Widener, PT, PhD, Professor, Samuel Merritt University

Valerie Block, PT, DPTSc candidate, Post Professional Student, University of California – San Francisco/San Francisco State University

Cynthia Gibson-Horn, PT, Adjunct Clinical Instructor, Samuel Merritt University

Diane Allen, PT, PhD, Professor, University of California – San Francisco/San Francisco State University

Keywords: Participation, Ataxia, Balance-Based Torso Weighting, Posture

Purpose/Hypothesis: Unsteadiness and decreased motor control during standing and gait put people with cerebellar ataxia at greater risk of falling and sustaining injuries. Strategic placement of light weights on the torso with balance-based torso weighting (BBTW) has improved gait velocity, cadence, standing stability, and fall rate in people with multiple sclerosis, some of whom have ataxia. This was the first study testing BBTW in people with cerebellar ataxia. Our purpose was to determine if BBTW could increase standing stability and functional movement during a single 1.5-hour session for people with ataxia and healthy matched controls. We hypothesized that people with ataxia would have improved measures of static standing and physical functioning with BBTW compared to no-weight conditions. We also hypothesized that healthy controls would show increased standing stability and function compared to people with ataxia.

Subjects: 10 participants with cerebellar ataxia, 10 healthy age- and sex-matched controls.

Materials/Methods: Participants completed the Activity-Specific Balance Confidence Scale. People with ataxia were assessed using the Scale for the Assessment and Rating of Ataxia. Six accelerometers were attached to the torso and extremities. Participants were asked to stand on a firm surface for 30 seconds with eyes open then eyes closed, and stand on foam for another 30 seconds with eyes open then eyes closed. If balance was lost, number of seconds prior to loss of balance was recorded. Participants performed the timed up and go (TUG) test. A vest-like garment was donned and directional instability was assessed in standing using a methodical series of perturbations and resisted rotations at the shoulders and pelvis. Light weights (totaling 0.25-2 pounds) were strategically applied to improve reactive control to balance challenges. The standing and TUG tests were repeated with the weights on. Paired t-tests compared within-group differences with and without weights. Independent t-tests compared between-group differences.

Results: Healthy controls but not people with ataxia had a statistically significant decrease in number of seconds taken to perform the TUG when weighted (p < .001). The number of seconds that people with ataxia successfully stood on the firm or foam surface was significantly higher with weighting (p=.003); all healthy controls stood for the maximum time of 120s in weighted and unweighted conditions.

Conclusions: Strategic weighting improved standing stability with eyes open and closed but not necessarily gait velocity in people with ataxia. Future analyses will examine postural sway with and without weights and potential plasticity when weights are worn daily.

Clinical Relevance: Heavy weights to control ataxia may be unnecessary if very light weights can improve standing stability and reactive control to directional balance challenges. Increasing gait speed may not be the goal in ataxia. However, improved stability may provide the needed impetus for increased participation in exercise or physical activity in this population.

Widener, Gail L, PT, PhD; Block, Valerie , PT, DPTSc candidate; Gibson-Horn, Cynthia , PT; Allen, Diane D, PT, PhD. Changes in Standing Stability with Balance-Based Torso-Weighting in People with Cerebellar Ataxia: a Pilot Study.. Poster Presentation. IV STEP Conference, American Physical Therapy Association, Columbus, OH, July 17, 2016. Online.