The Impact of Real-World Vibration Feedback Gait Retraining on Gait Biomechanics in People With Chronic Ankle Instability
Condition: Chronic Ankle Instability
Study type: Interventional

Summary: 
      People with chronic ankle instability (CAI) demonstrate altered gait or walking mechanics
      which cause people to walk on the outside of their foot and increases the risk of additional
      ankle sprains, abnormal cartilage strain, and early joint degeneration. Evidence indicates
      that common treatments for CAI do not impact gait, leaving unresolved impairments that can
      lead to lifelong disability. Recent lab-based gait retraining with visual and auditory
      feedback has immediately improved walking mechanics. However, real-world training is
      hypothesized to generate long-term changes by incorporating short, frequent training sessions
      over a variety of surfaces. These are key training parameters to produce lasting change.
      Pilot data using real-world vibration feedback (RW-VF) suggest that a single session
      immediately improves walking mechanics with changes lasting for up to 5 minutes. Despite
      promising initial results, there remains a critical need to determine the impact of multiple
      RW-VF sessions as an initial step to developing a protocol capable of long-term improvements.
      The purpose of this proposal is to determine the extent to which 2-weeks of RW-VF restores
      gait biomechanics in those with CAI. Twenty people with CAI will be enrolled and complete a
      two-week gait retraining protocol with vibration feedback. Walking mechanics before,
      immediately after, and 1 week and 4 weeks following the training will be compared. These
      contributions can be significant as positive results will support a paradigm shift in
      treatments for people with CAI and lay the foundation for large scale clinical trials aimed
      at optimizing long term gains. The outcomes of future research have the potential to advance
      evidenced based rehabilitation interventions not only for people with CAI but also for people
      who have sustained a variety of musculoskeletal injuries as there is strong evidence that
      other lower extremity pathologies cause lifelong limitations, including changes in walking
      mechanics which lead to degenerative changes to other joints.
    

Detailed description: 
      Background: There are 3.1 million lateral ankle sprains in the United States per year, of
      which about 40% will develop persistent limitations leading to chronic ankle instability
      (CAI). People with CAI demonstrate altered walking gait mechanics including increased
      inversion (ie: the foot rolling outward) and a lateral shift in the location of the center of
      pressure (COP) under the foot. These changes cause people to walk on the outside of their
      foot and increases the risk for additional ankle sprains, abnormal cartilage strain, and
      early post traumatic ankle arthritis (PTOA). Evidence indicates that common treatments for
      CAI do not impact gait, leaving unresolved impairments that can lead to lifelong disability.
      Recently walking with novel sensory feedback techniques (visual, auditory, and visual
      stimuli) has immediately improved walking mechanics during laboratory training. However,
      real-world (RW) training is hypothesized to generate long-term changes by incorporating
      short, frequent training sessions over a variety of surfaces which are key training
      parameters to produce lasting change. Vibration feedback (VF) is currently the only tool
      capable of being deployed in the real world. Recent pilot data suggest that a single VF
      training session in the RW immediately improves ankle and COP position with changes lasting
      for up to 5 minutes. Despite these promising initial results, there remains a critical need
      to determine the impact of multiple real-word vibration feedback (RW-VF) sessions as an
      initial step to developing a protocol capable of long-term improvements.

      Purpose: The purpose of this proposal is to examine the effectiveness of a new treatment
      approach by determining the extent to which 2-weeks of RW-VF restores gait biomechanics in
      those with CAI.

      Design: Cohort Study Methods: Kinematic and kinetic data will be captured from 20
      participants with CAI at two baseline training sessions within 48 hours of each other (B1 and
      B2) while the participant walks on an instrumented treadmill. These data will be used to
      calculate the minimal detectable change (MDC), which is the stability of the walking
      measures. Following B2, participants will be fitted with the VF tool and complete the first
      of six training sessions. During training sessions, participants will walk six standardized
      but unique 1-mile RW routes with VF within a two-week time period. The order of the routes
      will be determined by a random number generator. Three additional biomechanical walking
      assessments will be completed within 72 hours of (P-2), one week following the final training
      (F-1), and 4 weeks following the final training (F-4).

      Data Analysis: The primary analysis will determine the impact of RW-VF on COP location during
      the stance phase of walking in people with CAI. COP location will be compared before and
      after treatment (B1:P-2) using paired t-tests to determine the immediate impact of RW-VF
      training. The change between B1 and P-2 will be compared to the MDC to rule out measurement
      error. Next, COP location between B1 and F-1, and B1 and F-4 will be calculated to determine
      the extent to which the COP change is retained and compared to the MDC to rule out
      measurement error. Finally, COP data from posttest and retention timepoints will be compared
      to a database of walking biomechanics data from healthy controls using independent t-tests to
      determine similarities between people with and without CAI following training. The secondary
      analysis will repeat the primary using ankle position in the frontal plane (inversion/
      eversion) during stance.

      Significance: These contributions have the potential to be significant because positive
      results will support a paradigm shift in treatments for people with CAI. Positive results
      will also lay the foundation for large scale clinical trials comparing the current standard
      of care to the standard of care with the addition of RW-VF training to optimize long term
      gains. The outcomes of future research have the potential to advance evidenced based
      rehabilitation interventions not only for people with CAI but also for people who have
      sustained a variety of musculoskeletal injuries as there is strong evidence that other lower
      extremity pathologies cause lifelong limitations, including changes in walking mechanics
      which lead to degenerative changes to other joints.
    

Intervention name(s): Real-world vibration feedback gait retraining
Intervention type(s): Other
Intervention description(s): Participants will walk with a vibration feedback tool attached to their shoelaces. A small force sensing resistor is taped to the foot bed of the shoe under the lateral foot and a vibration motor is placed over the outside of the ankle with a strap. When a participant walks on the outside of their foot, they will exceed the pressure threshold and activate the feedback which signifies an incorrect foot placement. The feedback is intended to prompt a correct foot placement on the subsequent step. Participants will use the same feedback tool for 6 real world training sessions.
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Intervention model description: All CAI participants will be assigned to the intervention arm and will all receive the same treatment (6 sessions of RWVF gait retraining in 2-weeks). Posttest data from CAI participants in arm 1 will be compared to data from pre-collected de-identified healthy control data.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: ankle; walking; biofeedback