Learning From Falling: Perturbation-based Training to Prevent Falls in Older Adults
Condition: Accidental Falls
Study type: Interventional

Summary: 
      The investigators will evaluate the difference between a commonly accepted paradigm of
      balance training (BT) and a more dynamic and task specific form of balance training,
      perturbation-based training (PBT) in older adults. BT is a key evidenced based strategy for
      preventing falls in older adults, however it needs to be regular (2hours/week) and long term
      (>6moths) while the average effect is only moderate (24%). The reason for the moderate effect
      on falls is like to be the non-specific stimulus presented during BT. That is, training tends
      to be quasi-static and slow and largely based on movements described as strength training.
      However, when an individual loses balance, they are most often required to implement a rapid
      and dynamic response. Furthermore, while older adults who are unable to recover balance well
      have generally lower strength, our recent work has demonstrated that it is not their force
      producing capability that limits them. Rather it is the ability to access moderate levels of
      muscular force very rapidly and early in the recovery step that differentiates successful
      versus unsuccessful recovery of balance. Importantly, the ability to produce an effective and
      rapid recovery step is predicative of avoiding future real world falls.

      An emerging fall prevention training regimen is perturbation-based training (PBT). PBT
      involves rapidly disrupting balance requiring the participant to take rapid steps to recover
      balance. This is commonly achieved on a laboratory treadmill equipped with a safety harness
      to prevent actual falls during training. By simulating "real-world" balance challenges such
      as slips and trips, PBT provides a direct means for learning how to recover balance and avoid
      falls. It has been demonstrated that with only a few PBT sessions, older adults make rapid
      and dramatic improvements in balance recovery performance, retain the skills long-term and
      potentially suffer fewer falls over extended periods. This study builds on the previous
      published work of the PI that describes the key factors related to differences in balance
      recovery performance, the neuro-motor coordination strategies used during successful and
      unsuccessful recovery, and currently unpublished pilot studies indicating the efficacy of
      PBT. To date studies have not directly compared BT regimes recommended by the American
      College of Sports Medicine (ACSM) against PBT, nor have they evaluated the influence of
      training on the incidence of real-world falls. In part this may be because PBT currently
      requires the use of expensive, laboratory treadmills and as such is not accessible by the
      average independent, community dwelling older adults. A specific randomized study is required
      and our overall purpose for this study is to compare the balance recovery performance of
      older adults following either BT or PBT, evaluate differences in the incidence of real-world
      falls, and develop a safe, effective and portable device for use in future community PBT
      training studies. The short-term goals are to determine the effect of PBT versus BT and the
      neuro-motor mechanism of improved recovery behavior.

      Aim 1: To evaluate differences in balance recovery behavior in older adults following either
      balance training (BT) and perturbation-based training (PBT) and the incidence on real-world
      falls.

      H1: Balance recovery performance will improve in both BT and PBT groups but will be
      significantly better in those completing PBT when compared to BT.

      H2: Improvements in balance recovery behavior will be related to improved coordination and
      neuro-motor control strategies.

      H3: Real world loss of balance events will be similar in both BT and PBT but incidence of
      resulting falls will be lower in the PBT group.
    

Detailed description: 
      APPROACH

      1) The main study The main study to investigate the difference between BT and PBT is a
      parallel-group randomized controlled trial with 6 months follow-up from baseline to determine
      the effect of PBT program on stepping behavior and fall incidence in community-dwelling older
      people. The study has been designed in accordance with the Consolidated Standards of
      Reporting Trials (CONSORT) statement48.

      Participants, recruitment and screening Participants will consist of community-dwelling
      adults aged over 65 years without a recent history of falls (one or more falls in the past 12
      months). All participants will be required to obtain medical clearance from their general
      practitioner prior to participation in the study. Exclusion criteria will be neurological,
      cardiovascular or musculoskeletal impairment that adversely affect balance or limit
      involvement in the intervention, diagnosis of dementia, cognitive impairment (score<24 on
      Mini Mental State Examination after adjustment for age and years of education49), functional
      disability/limitation in activities of daily living (Score>3 on Bayer Activities of Daily
      Living Scale50), osteoporosis, use of medication that affects balance or causes dizziness
      (e.g. psychotropics) and participation in supervised exercise one or more times per week.

      Random allocation and concealment Randomization will be performed following baseline
      assessment by personnel not involved in recruitment, training or assessments. Participants
      will be informed that they will receive one of two treatments. Due to the nature of the
      intervention, research personnel administering the treatments cannot be blinded to group
      allocation. However, the personnel that perform the prospective falls evaluation will be
      blinded to group allocation.

      Intervention BT group. This group will undertake 12 weeks of twice weekly BT in accordance
      with ACSM guidelines. Training will be conducted in small groups under the supervision of a
      trainer. Training will involve mobility, resistance and balance training components.

      PBT group. The PBT protocol uses multi-directional surface translations to provoke rapid
      compensatory stepping responses to recover balance. The protocol is a modified version of the
      stepping (but not grasping) component of the PBT program described by Mansfield et al., which
      was designed to improve rapid stepping reactions and minimize foot collisions in accordance
      with well-established principles of motor learning including individualization, specificity,
      progressive overload, and variability of training. At each session the PBT group will
      experience multi- directional disturbances to standing posture (forwards, backwards, left,
      right) delivered via translations of a motorized treadmill. 24 perturbations will be
      administered in a random sequence (with variation in timing, magnitude and direction) and
      interspersed with 30 s treadmill walking. Successful recoveries during training will be
      followed by an increase in the degree of difficulty, whereas consecutive failures will result
      in a return to the perturbation intensity that had previously been performed successfully.
      Our pilot testing indicates that the prescribed peak accelerations on our motorized treadmill
      to within ±3% can be achieved. The occurrence of actual falls will be prevented via the use
      of a custom safety harness attached to an overhead cable instrumented with a force transducer
      used previously. One familiarization trial in each perturbation direction will be performed
      at 50% intensity at the beginning of the first training session. Training sessions will be
      terminated when the participant completes the planned number of trials or if the participant
      elects not to continue (e.g. feels tired, uncomfortable or unwell).

      Primary outcome measures The tether-release54 test will be used to determine whether training
      effects generalize to balance recovery reactions that are not part of the intervention. Loss
      of balance will be induced by releasing participants from static forward lean postures
      corresponding to 15%, 20% and 25% of their body weight on a horizontal restraining tether in
      accordance with the PI's previous work groups published procedures. Participants will be
      instructed to attempt to regain balance by taking a single, rapid step. Full body kinematics
      and ground reaction forces will be recorded during all balance recovery tasks using a 3D
      motion capture system (12-camera Motion Analysis) and force platforms embedded in the ground
      (AMTI, Watertown, USA). Outcome measures will be margin of stability at touchdown of the
      stepping leg, step leg kinematics (step length and velocity) and trunk kinematics (trunk
      angle and trunk angular velocity). All analysis will be performed using OpenSim57 in
      accordance with the PI's and his previous research units published methods.

      Secondary outcomes measures Falls frequency will be monitored over the 3 months of the
      intervention and following 3 months of follow up with monthly falls diaries. Participants
      will return monthly falls diaries (daily entries) to determine frequency, time, location and
      cause of falls and related injuries as per consensus recommendations for falls trials52.

      OVERALL SUMMARY

      The proposed investigation forms the basis of improved understanding of balance recovery
      training methods and are important steps for ongoing research into the efficacy of balance
      recovery training modes relative to reducing the incidence of falls. In particular, the
      proposed study is the necessary precursor to a large prospective study to evaluate the effect
      of balance recovery training on health and wellbeing of rural Montanans.
    

Intervention name(s): Balance recovery; Postural Sway
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Balance recovery by stepping ascertains the capability of the participant to recover when subjected to a loss of balance in the forward direction.
Attitudes towards exercise, fear of falling and mental wellness a psychosocial measures to ascertain the relationship between perceptions and physical capability.; Postural sway is a pseudo-static measure of postural control that evaluates a participants balance recovery ability when the perturbation does not require a dynamic step recovery.
Attitudes towards exercise, fear of falling and mental wellness a psychosocial measures to ascertain the relationship between perceptions and physical capability.
Other intervention name(s): Attitudes towards exercise; Fear of falling; Mental Wellness; Attitudes towards exercise; Fear of falling; Mental Wellness
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Balance Recovery