Preliminary investigation of the lateral postural stability of spinal cord-injured individuals subjected to dynamic perturbations.
STUDY DESIGN: A study of the impact of spinal cord injury (SCI) on seated balance was conducted by comparing the results obtained from experiments with able-bodied and SCI subjects. OBJECTIVES: The purpose of this preliminary study was to examine the lateral postural stability of seated individuals with SCI in a dynamic environment. SETTING: Experiments were conducted at the Cleveland Clinic Foundation in Cleveland, Ohio. METHODS: Controlled perturbations were applied to each subject, seated in a wheelchair, through the use of a servo-controlled tilt platform. The platform was rotated so as to create disturbances similar in nature to those experienced in the frontal plane during left turns in a vehicle. Four quadriplegic, four paraplegic, and five able-bodied subjects participated in this study. Kinematic information and center of pressure (COP) movement were recorded. RESULTS: None of the spinal cord-injured subjects was able to maintain his stability when exposed to the stronger perturbations, while all of the able-bodied subjects stayed upright for all of the trials. On an individual basis, injury level was not always indicative of balance. However, regression results suggest a correlation between ability to perform static leaning and dynamic balance (P<0.001). CONCLUSIONS: SCI subjects lost stability under dynamic conditions even though they were stable in the static situation. Initial results also raise some questions about where and when external support may be needed. Information of this nature could help to guide the design of new lateral supports with improved client acceptance.