Results using Stepping-over Response Training to Improve Walking in Individuals with Poststroke Hemiplegia

David L. Jaffe, MS

Objectives: The primary goal of this work has been to identify, test, and compare training techniques that improve locomotor function following Stroke. Improving walking leads to functional increases and additional daily living options. In addition, better gait, especially walking speed, reduces the risk of falls and subsequent injury, a serious Veteran problem.

Methods: The project compared two training interventions: stepping over real foam objects (Overground) and stepping over computer-generated objects (Treadmill). A total of 21 subjects with hemiplegia were randomized into one of the two training interventions. Six training sessions of approximately one hour each were scheduled over a two-week period. Twelve repetitions of stepping over ten obstacles constituted one session. Evaluations of locomotor function were performed prior to training, after the two weeks of training, and two weeks post-training and consisted of a Balance Test, Walking Test, Obstacle Test, and 6-Minute Walk. During all procedures, a therapist guarded the subject for safety.

Overground training intervention: subjects stepped over foam objects in a hallway spaced 15 to 22 inches apart as calculated from the subject's stride length.

Treadmill training intervention: subjects walked on a treadmill at their normal walking speed and were held safely in place using an overhead harness. A color video camera was directed at the subject's legs from the right side. A computer introduced a stationary image of a rectangular object of a selected height and length at the subjects' feet. The subject wore a head-mounted display to view the composite camera and computer image. As the treadmill ran, the subject was instructed to step over the virtual object on each step. The computer detected any intersection of the users' feet with the computer-generated object and produced audio and vibro-tactile feedback on these "collisions" with these virtual objects.

Results: The results demonstrated improvements for the twenty-one subjects in both training groups in walking speed, cadence, stride length, and ability to step over stationary objects. Treadmill intervention data showed significantly increased walking speed and stride length measures for both normal and fast walking evaluation tests. Eighty to ninety-five percent of these improvements were retained two weeks after the completion of the training.

Conclusions: The treadmill training technique produced an immediate and familiar visual stimulus for stepping and provided a unique perspective unavailable to a subject looking down at his/her feet or viewing their walking in a mirror. The treadmill and harness system offered a safe environment in which to respond to therapist's suggestions and try new strategies of moving and stepping. The therapist could view (via the computer's CRT) the same display as the subject to observe the subject's response to movement suggestions. The immediacy of the visual feedback when successfully negotiating with a virtual obstacle reinforced the subject's positive efforts. The computer added the ability to 1) fully document each session, 2) use objects of standardized size and placement, and 3) easily change the height and width of the object as the subject improved. A further study of techniques to improve walking is being pursued through a Merit Review proposal.

Funding Acknowledgment: This study was funded by the VA Rehabilitation Research and Development Service, Merit Review project E1829-R.