Augmenting Ankle Plantarflexor Function and Walking Capacity in Children with Cerebral Palsy

PROJECT SUMMARY A child’s ability to walk effectively is essential to their physical health and general well-being. Unfortunately, many children with cerebral palsy (CP), the most common cause of pediatric physical disability, have difficulty walking and completing higher-intensity ambulatory tasks. This leads to children with CP engaging in levels of habitual physical activity that are well below guidelines and those of children without disabilities, which in turn contributes to many secondary conditions, including metabolic dysfunction and cardiovascular disease. There is broad clinical consensus that plantarflexor dysfunction is a primary contributor to slow, inefficient, and crouched walking patterns in CP; individuals with CP need more effective treatments and mobility aids for plantarflexor dysfunction. To meet this need, this proposal aims to evaluate a holistic strategy to address impaired mobility from plantarflexor dysfunction in CP using a lightweight, dual-mode (assistive or resistive) wearable robotic device. This strategy combines two complementary techniques: (1) targeted ankle resistance for neuromuscular gait training that provides precision therapy to elicit long-term improvements in ankle muscle function, and (2) adaptive ankle assistance to make walking easier during sustained, high-intensity, or challenging tasks. The first specific aim is to quantify improvement in ankle muscle function and functional mobility following targeted ankle resistance gait training in ambulatory children with CP. The primary hypothesis for the first aim is that targeted ankle resistance training will produce larger improvements in lower-extremity motor control, gait mechanics, and clinical measures of mobility assessed four- and twelve-weeks post intervention compared to standard physical therapy and standard gait training. The second specific aim is to determine the efficacy of adaptive ankle assistance to improve capacity and performance during sustained, high-intensity, and challenging tasks in ambulatory children with CP. The primary hypothesis for the second aim is that adaptive ankle assistance will result in significantly greater capacity and performance during the six-minute-walk-test and graded treadmill and stair stepping protocols compared to walking with ankle foot orthoses and walking with just shoes. Both Specific Aims will explore the participant characteristics (e.g., age, gender, GMFCS level, walking speed, spasticity rating) that are associated with the greatest improvement in outcomes following each intervention to provide guidance for future clinical and at-home implementation. The proposed studies will establish fundamental knowledge on the ability for adaptive ankle interventions to treat walking impairment relative to standard of care in CP.