Clinical Applications of FES-cycling to SCI and Stroke Subjects for Smoother and Symmetrical Movement Patterns

Pedaling exercise on a bicycle ergometer is possible for spinal cord injured (SCI) and stroke patients who are preparing to maintain or recover functional movement abilities. The aims of this study are to develop tailor-made stimulation paradigms that can be applied to varied groups of subjects including complete and incomplete SCI, and stroke subjects for FES-cycling training. Compared to paralyzed limbs in complete SCI subjects, asymmetrical movement patterns caused by muscle weakness or spasticity have often been found in incomplete SCI and stroke subjects. Thus, additional quantitative indices are needed to represent the asymmetrical movement in cycling ergometer from kinematical and muscle activity aspects. To measure the cycling smoothness, roughness index (RI), derived from curvature of instantaneous cycling speed, is used to measure kinematical information. The symmetry index (SI) measures the similarity of muscle activities recorded form affected and unaffected limbs. RI represents the kinematical output of pedaling due to the stimulation or voluntary movement in stroke subjects. However, the muscle power in the unaffected side of stroke subject might dominate the entire pedaling cycle. These two parameters provide additional guidelines for tuning the stimulation schemes for incomplete SCI and stroke subjects.