Quantifying Patient-specific Changes in Neuromuscular Control in Cerebral Palsy: Adaptation and Biofeedback During Gait

Prior research has shown that children with cerebral palsy (CP) use simplified motor control strategies compared to nondisabled (ND) peers, and that these differences in motor control are associated with walking function. While we can quantify motor control during activities like walking, the processes by which a child with CP adapts and learns new movement patterns are poorly understood.

This research will use two paradigms to evaluate adaptation and motor learning in children with CP: walking on a split-belt treadmill and responding to multimodal biofeedback. Walking on a split-belt treadmill, which has two belts set at different speeds to induce asymmetry during walking, has been commonly used to evaluate adaptation in other clinical populations. Responding to multimodal feedback can also be used to evaluate an individual's capacity to adapt their walking pattern. This research will use a real-time multimodal feedback system that targets plantarflexor activity, a key muscle group that is often impaired in CP. Sensorimotor feedback will be provided using a lightweight, body-worn robotic device that provides adaptive ankle resistance and step-by-step audiovisual feedback will be provided based on muscle activity from the plantarflexors using a visual display and audible tone. This research will quantify adaptation rate (e.g., change in soleus activity or step length symmetry) in response to these perturbations, and observe the impact of repeated practice or orthopedic surgery on walking function (e.g., change in walking speed). The specific aims are to:

Aim-1: Quantify adaptation rates in children with CP. We will quantify adaptation rate in response to three perturbation experiments: split-belt treadmill walking, sensorimotor feedback, and audiovisual feedback. The primary hypotheses are that children with CP will exhibit reduced adaptation rates compared to ND peers, and that adaptation rates will be associated with function (Gross Motor Function Measure, GMFM-66).

Aim-2: Determine whether adaptation rates change in response to repeated multimodal feedback training. We will evaluate children with CP who undergo six weeks of multimodal biofeedback training (20-min, 2x/week) or orthopedic surgery. The primary hypothesis is that multimodal feedback training will produce greater changes in adaptation rates than orthopedic surgery.

Aim-3: Determine whether changes in gait after treatment are associated with adaptation rates. Gait analysis will be performed to determine whether baseline adaptation rates are associated with changes in gait after treatment. The primary hypotheses are that baseline adaptation rates will be associated with changes in muscle, joint, and whole-body performance.