Improving Stepping-Over Responses in the Elderly using Simulated Obstacles

Poster

David L. Jaffe, MS, Ellie L. Buckley, MS PT, Cheryl D. Pierson-Carey, PT MS, and David A. Brown, PT PhD

Rehabilitation R&D Center, Palo Alto VA Health Care System and Programs in Physical Therapy, Northwestern University Medical School

Objectives: The goal of this project is to design and evaluate clinical interventions to train elderly individuals at high risk for falling. These interventions employ techniques to monitor their stepping-over perfomance and response times.

The specific objectives are to develop a clinical system to measure and improve stepping-over performance, train effective movement strategies, and to demonstrate clinical efficacy of the system in a randomized, controlled intervention study.

Clinical Relevance: Death results from 75% of falls in the 12% of the population that are over 65. The United States Public Health service identified the reduction of falls as a national health priority in it's "Healthy People 2000: National Health Promotion Disease Prevention Objectives". The ability to step over objects is an essential component of ambulation that enables a person to reduce the risk of falling. The frail elderly, a growing Veteran population, would benefit from this research.

Methods: Subjects will participate in one of the three inverventions: stepping over a) real, b) imaginary, and c) virtual objects.

Subjects will be asked to step over a course of 10 foam obstacles.

Subjects will be instructed to "step higher" and "step longer" while walking on a motorized treadmill.

Subjects will be asked to step over virtual obstacles while walking on a motorized treadmill. A composite video image of the subjects' lower body and virtual obstacles will be presented in a head mounted display. Subjects will be asked to step over the virtual obstacles. Shoe mounted vibrotactile stimulators will provide feedback of "collisions" with the virtual obstacles.

Subjects' stepping-over performance before and after a 4 week intervention period will be measured on a standard course of foam obstacles.

Results: The pilot work has led to the following preliminary results:

The most successful technique for presenting virtual objects involved displaying a side-view of stepping on a treadmill while the viewer repeatedly negotiated computer-generated obstacles.

Similar stepping strategies are employed in all three interventions.

A small group of elderly subjects were better able to negotiate an overground obstacle course after 3 training sessions using computer-generated obstacles.

Conclusions: Clinical trials are currently underway with a population of Veterans over the age of 60 who have mild to moderate COPD. The completed study will identify the relative merits of the three interventions with this population.

Acknowledgments: VA Merit Review E2167-2RA