Title page for ETD etd-12222009-140431

Type of Document Dissertation
Author Parijat, Prakriti
Author's Email Address pparijat@vt.edu
URN etd-12222009-140431
Title Preventing slip-induced falls in older adults: perturbation training using a moveable platform and virtual reality
Degree PhD
Department Biomedical Engineering
Advisory Committee
Advisor Name Title
Lockhart, Thurmon E. Committee Chair
Agnew, Michael J. Committee Member
Gabbard, Joseph L. Committee Member
Madigan, Michael L. Committee Member
Roberto, Karen A. Committee Member
  • slip-induced fall
  • motor learning
  • virtual reality
  • perturbation training
Date of Defense 2009-08-13
Availability restricted
Slip-induced fall related injuries are a serious public health issue among older adults leading to considerable mortality, morbidity, and immobility. Existing proactive exercise interventions have produced mixed results on the success of reducing fall accidents. A training intervention may be effective in reducing slip-induced falls, if it can help older adults to practice movements related to recovery responses.

The purpose of this study was to evaluate two different training interventions using a moveable platform and virtual reality in order to improve reactive recovery in older adults. Thirty-six older adults were recruited and randomly assigned to three groups (moveable platform training, virtual reality training, and control). The training groups underwent three sessions including baseline slip, training, and transfer of training on a slippery surface. The control group underwent three similar sessions as the training groups, with the training session replaced with a normal walking session. Kinematic, kinetic, and EMG data were collected during all the sessions. The moveable platform training group was repeatedly exposed to simulated slips induced by anterior-posterior movement of a platform. The virtual reality training group was repeatedly exposed to perturbation induced by visual tilts in the virtual environment while walking on the treadmill. Various biomechanical and neuromuscular characteristics were identified to quantify the effects of training.

The results indicated a beneficial effect of both training methods in improving recovery reactions in older adults via proactive and reactive adjustments. The reactive adjustments involved faster response to a slip perturbation mediated by reduced time for onset and peak muscle activation (specifically knee flexor), reduced knee and ankle coactivity, reduced time for peak knee, hip, and trunk angles, and angular velocity. The proactive adjustments involved an increased center-of-mass velocity and transitional acceleration of center-of-mass. The overall fall frequency was reduced in the training groups as compared to the control group through improvements in proactive and reactive responses.

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