Advanced computer model of orientation and mobility used by visually impaired individuals

Bruce Blasch, Ph.D., Vincent Ramsey, CSCS, DAV

Decatur VAMC

Objectives: The objective of this three-year study is to develop an advanced computer model of Orientation and Mobility used by individuals with a visual impairment and to develop a "gold standard" database of gait related information for the visually impaired population. This study will build on the previous work known as RoboCane that developed and validated the modeling of symmetrical gait, cane movement, hand positioning and analysis of cane coverage. Specific goals in this research are to develop additional features, including a 3-dimensional figure, options for asymmetrical gait patterns, abilities to respond to drop-offs, enhanced environmental representations, and the parameters of different commercially available Electronic Travel Aids (ETAs). The resulting program model will be displayed through the use of three-dimensional graphics with the point of view controlled by the user.

Methods: Project staff is developing a software program using a three-dimensional full body figure. This program will represent a legally blind person using a cane. In addition, the opportunities to introduce asymmetrical gaits, specifying enhanced environmental representations in a floor plan format, and added options of using an ETA are being incorporated. The validity of the model will be verified using comparisons of the measurements obtained through biomechanical video analysis of actual mobility movement of travelers using a long cane. Video analysis will also be used to verify the accuracy of field methods for obtaining basic input measures. After the model has been validated, researchers will run Monte Carlo Simulations to generate a probabilistic estimate of safety index for a sample of veterans obtaining Orientation and Mobility training at the VA Blind Rehabilitation Centers (BRCs). Based on the results from the Monte Carlo Simulations, researchers will interact with clinical staff to explore options for veterans going through the BRC program. In addition, the kinematic analyses conducted on each subject during this study will provide a "gold standard" database of gait related parameters for visually impaired persons.

Results: At this time approximately thirty visually impaired subjects have been tested.

Preliminary analyses on these subjects indicate significant differences in the gait velocity, stride length, stride rate and other segmental and angular kinematics, between visually impaired persons and age-matched sighted subjects.

Conclusions: Significant differences exist in the functional gait patterns of visually impaired individuals as compared to their sighted counterparts. These differences may impact the ability of visually impaired persons to safely and effectively navigate through the environment.

Acknowledgments: This study was funded by the Veterans Affairs Medical Center, Rehabilitation Research & Development Center.