Motor Outcomes and Neural Correlates of Asymmetrical Gait Training in Children With Acquired Hemiplegia

Effective rehabilitation after acquired brain injury is essential for reducing the impact of the leading cause of pediatric disability in the United States. Neuroplastic changes in response to physical therapy are likely different in children compared to adults because children are continuing to experience developmental brain maturation while also experiencing the neural changes associated with injury and rehabilitation. The interaction between these two processes is poorly understood but presumably critical for maximizing long term outcomes. Using biomarkers to measure and predict rehabilitation-induced changes will improve rehabilitation prognosis and will facilitate the development of rehabilitation interventions that optimize neuroplastic potential in children. The objectives of this pilot study are to investigate the motor and neural responses to two different rehabilitation programs in children and adolescents with chronic hemiplegia from prior stroke. Participants will be randomly assigned to receive conventional physical therapy or an asymmetrical gait training program. Conventional physical therapy will include activities such as gait and balance training and muscle strengthening. The asymmetrical gait training program uses new technology to train each leg at a different speed during walking practice. Measurements of motor and neural function will occur at five timepoints before, during and after treatment. Motor function measures will include gait symmetry ratios, walking speed, community step activity, and participant and caregiver ratings on self-identified walking goals. Neural measures will include motor response characteristics of muscle contractions elicited in two lower extremity muscles by transcranial magnetic stimulation of the injured cortex. We will also establish a genetic database to identify the presence or absence of two genetic variants [Apolipoprotein E (ApoE Є4) and val66met Brain-derived neurotropic factor (BDNF) polymorphisms] associated with decreased potential for neuroplasticity for planning future investigations. The results will be used to inform the design of larger studies evaluating physical therapy treatments that maximize the capacity of the child's brain to change after neurological injury and identifying predictors of rehabilitation-induced neuroplasticity in children.