Cerebral palsy (CP) is a movement disorder characterized by deficits in strength and coordination. The subsequent gait deficits associated with CP lead to a progressive decline in function due to the secondary effects of having a movement disorder during development. Interventions seeking to mitigate these effects have only been partially successful because they have not addressed both muscle recruitment (i.e. strength) and coordination within one, top-down therapy. Recently, we developed a wearable adaptive resistance therapy that is able to address both of these aspects with promising results for improving neuromuscular control, metabolic efficiency, and functional mobility. To maximize the efficacy of this intervention, two important considerations must be addressed: 1) What is the appropriate level of resistance to prescribe for maximizing neuromuscular response as children acclimate to the intervention? 2) What is the overall trajectory in training effects from this therapy and are these effects maintained after the therapy stops? In addition, there is limited understanding of the underlying mechanisms of observed improvements in neuromuscular control with this novel therapy. The high levels of co-contraction in children with CP have been attributed to deficits in stretch reflex modulation, but whether or not improvements in reflex modulation are responsible for the observed decreases in ankle co- contraction with wearable adaptive resistance has not yet been explored. The main objective of this research proposal is to further investigate a wearable adaptive resistance intervention for children with CP. The first specific aim is to assess the acclimation to adaptive resistance by measuring the neuromuscular response of children with CP, across five visits, as a low, moderate, and high level of resistance is applied while walking. The second specific aim to quantify the time-course and maintenance of training effects for the ten participants by measuring changes in neuromuscular control (i.e., co-contraction about the ankle and the complexity of neural control) and reflex modulation (via H-reflex testing) across five training visits with wearable adaptive resistance, as well as a two-week post-training follow-up visit. Our primary outcome variable for Aim 1 ix plantar flexor activation magnitude, relative to baseline, while walking with resistance. Our primary outcome variables for Aim 2 are ankle co-contraction level, neural control complexity (as determined by a muscle synergy analysis), and reflex modulation (via H-reflex testing) while walking without resistance. The completion of this work will improve our understanding of wearable adaptive resistance, including fundamental knowledge about appropriate training levels and underlying mechanisms, with the ultimate goal of developing an intervention that can enable physical activity for children with CP, allowing them to engage with their peers and environment for healthy development and functional independence.
Cerebral palsy is characterized by a progressive decline in mobility due to gait dysfunction caused by deficits in strength and coordination. This proposal investigates a novel wearable adaptive resistance therapy for improving neuromuscular control and walking outcomes in this patient population. Completion of this work will contribute to a better understanding of the factors necessary for successful rehabilitation of children with neuromuscular impairment.
