Abstract—Advances in combat medical care are allowing severely wounded individuals to survive injuries that would have previously proven fatal. Severely wounded individuals commonly demonstrate limitations in gait performance due to loss of physical function associated with the injuries, and, we believe, due to limitations in current training techniques. The purpose of this case report is to describe the effect of a nine session training program using virtual reality and real-time feedback on gait performance.

I. INTRODUCTION DVANCES in combat medical care are allowing severely wounded individuals to survive injuries that

would have previously proven fatal. Following acute medical management severely wounded individuals undergo intensive rehabilitation in order to maximize function. Limitations in gait performance often persist due to loss of physical function associated with the injuries, and, we believe, due to limitations in currently available training such as poor reliability of observational assessment and limited feedback capabilities. By allowing presentation of rapid and accurate feedback, virtual reality and real-time feedback hold great promise for the improvement of gait performance in the polytrauma patient.

A 38 year old male who had experienced widespread injury participated in nine training sessions over three weeks. The patient who was over three years post injury had experienced pelvic fractures, spinous process fractures, below the knee (transtibial) amputation on the right and ankle fusion on the left. In spite of extensive rehabilitation the individual continued to demonstrate significant deviations from normal gait. Training was conducted using a one-of-a-kind Computer Assisted Rehabilitation Environment (CAREN) system. The CAREN includes a 21 foot diameter domed screen and instrumented treadmill, allowing individuals to walk through an immersive virtual reality environment.

Training consisted of nine 30 minute sessions during which the patient received visual and verbal feedback. An Avatar (animated representation of the patient) driven by motion capture data, trunk marker trajectory data as well as two objects representing transverse plane motion of the trunk and pelvis were presented on the screen in front of the subject. The treating therapist was presented with graphs

Manuscript received July 1, 2008. This work was supported in part by the Military Amputee Research Program.

J.M. Wilken is Director, Military Performance Laboratory, Center for the Intrepid, Fort Sam Houston, TX 78234 USA (phone: 210-916-1478; fax: 210-916-9016; e-mail: Jason.wilken@amedd.army.mil).

containing real-time frontal, sagittal and transverse plane motion of the pelvis. The patient’s attention was directed toward the visual feedback in order to communicate desired changes in gait performance. The patient was also encouraged to independently develop strategies to achieve the desired changes. The therapist used the graphs to determine if the verbal feedback provided to the patient and the patient’s attempts to improve gait performance were successful in achieving the desired goals.

The patient reported several benefits from training including perceived improvements in gait performance and endurance. Although the patient reported muscle soreness due to training he expressed interest in participating in additional training sessions as a result of the perceived gains. At the end of ninth training session the patient demonstrated large quantitative improvements in both frontal and transverse plane symmetry of trunk motion (Fig. 1). Improvements obtained during CAREN training were also demonstrated during follow-up over-ground testing (Fig. 1).

II. CONCLUSION The use of real-time feedback holds great potential for

improving physical performance following severe musculoskeletal injury. Although initial results are promising, there remains a limited understanding of the most appropriate forms of feedback, the dosage required to achieve and sustain performance gains as well as the factors that predict training success.

Virtual Reality and Real-Time Feedback to Improve Gait Performance in a Polytrauma Patient

Jason M. Wilken and Benjamin J. Darter

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TRUNK FRONTAL PLANE MOTION SYMMETRY

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Fig. 1. Symmetry ratio data demonstrating improvements in trunk motionsymmetry during initial (OG1, CA1) and follow-up (OG2, CA9) testingsessions. OG= over-ground testing, CA= CAREN testing, NORM= datafrom uninjured control subjects

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