A major goal of patients with spinal cord injury (SCI) is to regain walking ability, as limitations in mobility can affect most activities of daily living In addition, patients with SCI may experience a higher incidence of falls due to impaired balance and gait. Further, the consequence of falls in patients with SCI is much greater than that for healthy older adults. Dynamic balance control plays a crucial role during locomotion in human SCI. Thus, improved dynamic balance may facilitate locomotion in this population. Current balance training paradigms can be effective in improving balance during standing, but are less effective in improving dynamic balance during locomotion in humans with SCI. Thus, there is a need to develop new paradigms for improving dynamic balance and locomotor function in patients with SCI.
The goal of this proposed research is to explore motor adaptation to a mediolateral force applied at the pelvis during walking in humans with SCI and test whether pelvis perturbation training paired with transcutaneous spinal direct current stimulation (tsDCS) will be effective in improving dynamic balance and locomotor function in humans with SCI. We postulate that providing a perturbation force to the pelvis during treadmill training will increase the activation of muscles used for maintaining lateral balance while walking. Further, repeated activation of particular sensorimotor pathways (through repeated exposure to a pelvic perturbation force) may reinforce circuits and synapses used for lateral balance control through a use-dependent neural-plasticity mechanism. However, the excitability of spinal cord neural circuitries may be depressed due to the reduced descending drive signals from the upper level control center after SCI, which may reduce the efficacy of neural plastic changes achieved following rehabilitation. The excitability of neural pathways is crucial for neural reorganization achieved following rehabilitation. Recently studies indicate that tsDCS may modulate the excitability of neural circuitries of the spinal cord in patients with SCI.
Thus, we postulate that controlled pelvis perturbation training paired with tsDCS will be more effective than that paired with a sham in improving dynamic balance and locomotor function in humans with SCI. Results obtained from this study will lead to an innovative clinical therapy aimed at improving balance and walking function in humans with SCI. Improvements in balance and walking function may allow for increased participation in community-based ambulation and activities, and significantly improve quality of life in humans with SCI. The improvements of scientific knowledge obtained from this study may be extended to other SCI patients with lower walking function, or other patient populations, such as individuals post-stroke.
This study is supported by NICHD/NIH, R01HD083314