Reactive Balance Training for Fall Prevention

Participants will be given thirteen slips and thirteen trips in stance and walking, followed by two slips and two trips at a higher intensity (posttest). Subjects would be consented if they would like to undergo fMRI pre and post-training. Participants not willing to undergo imaging would not be excluded. Three day training consisting of blocks of five consecutive gait-slips at varying intensities will be provided. Individuals with stroke would undergo an additional session (total 4 training sessions over 4 weeks (1session/week) since these individuals get easily fatigued and also might need more training sessions with sufficient rest interval to induce reactive adaptation. Training at a specific level will persist until the subjects show a recovery step response in at least 3/5 trials in a single block. Once subjects successfully adapt to this level, the perturbation intensity will be increased until they show a recovery response in at least 3/5 trials.

"Slips and trips could be induced under either of the limbs. The specialized walkway consists of two sliding platforms, each of which is mounted on two rows of low friction linear bearings (friction coefficient = 0.02). The base plate of each platform is bolted separately onto the top of a force platform embedded in the floor. An electronic-mechanical latch system is used to control the 2 states of the support platform; that is, the locked state for regular walking and the release state to initiate slipping are carefully controlled. The sliding top of the platform is released after the heel strike (vertical force to exceed 2% of the body weight). The slip distance would be adjusted between 30 to 60 centimeters depending upon the different population and their physical capacity."

During the first minute of each block, subjects would experience no perturbations followed by 3 minutes of single or multi-directional perturbations. A one minute break between each condition would be provided. Subject's fatigue would be assessed by Fatigue severity scale to determine the tolerability of 30 minute training protocol. The expected duration to complete the test would be a maximum of 1 hour including the preparation and training time.