Study Description:
This protocol will explore the use of multimodal signal acquisition techniques such as surface electromyography (sEMG), electroencephalography (EEG), dynamic ultrasound imaging (US), and motion capture for characterizing and modulating movement in children and young adults with cerebral palsy (CP). The protocol is divided into two parts. In Part I, participants will perform single degree of freedom movement tasks using three joints (ankle plantar flexion-dorsiflexion, knee flexion-extension, and wrist flexion/extension) with or without FES assistance, as well as walking on a treadmill. Real-time ultrasound imaging will be used to monitor their muscle movement during these tasks and they will perform a target achievement task based on this measured muscle movement. The hypothesis is that the ultrasound imaging technique will enable us to extract movement intent in real-time from the participants, and hence characterize (and correlate) their movement in multiple signal domains - brain activity, electrical muscle activity, muscle deformations, as well as resulting kinematics. In Part II, they will perform a knee flexion-extension task with or without FES assistance and with or without robotic exoskeleton assistance. The exploratory aim of this part is to investigate the feasibility of using real-time ultrasound imaging for control of a robotic exoskeleton and FES.
Objectives:
Primary Objectives: The primary objectives of this study are (1) to investigate the effectiveness of continuous real-time dynamic ultrasound imaging for tracking joint kinematics and (2) to evaluate its initial feasibility as a control signal for wearable exoskeletons and functional electrical stimulation through control of a virtual cursor in children and young adults with CP.
Secondary Objective: The secondary objective is to use this same multimodal data to characterize the temporal and magnitude relationships between movement initiation in the cortex measured by EEG, muscle electrical activation measured by sEMG, muscle deformation measured by US, and limb movement measured by motion capture, in children and young adults with CP and healthy controls.
Endpoints:
Primary Endpoints:
1. The correlation between measured joint kinematics and derived joint kinematics from ultrasound during single degree of freedom movements of the knee, ankle, and wrist.
2. The correlation between virtual cursor dynamics and the minimum jerk trajectory during the virtual cursor target acquisition task, with and without FES.
Secondary Endpoints:
1. To evaluate the relationship between the dynamics of sEMG activation and ultrasound-derived joint kinematics during a single degree of freedom movement task of the knee, ankle, and wrist - with and without FES - in children and young adults with CP
2. To evaluate the correlation between kinematics derived from US imaging of muscles as well as sEMG and the measured joint kinematics during treadmill walking in children and young adults with CP
Exploratory/tertiary Endpoints:
1. To evaluate the feasibility of using continuous real-time dynamic ultrasound imaging for control of a single degree of freedom task while wearing a robotic exoskeleton in children and young adults with CP
2. To evaluate the feasibility of using real-time continuous ultrasound imaging to guide closed loop control of functional electrical stimulation parameters during a single degree of freedom movement task
3. To evaluate the feasibility of using real-time continuous ultrasound imaging to guide the stimulation properties during FES and cause intended movement, while a robotic exoskeleton is used to provide resistance against such movement.
4. To characterize the time delays between cortical activation, muscular electrical activation, muscular mechanical deformation, and resulting kinematics of the joint during volitional movement.
5. To characterize the electrical (muscular) activation profiles, and mechanical muscle deformation profiles in children and young adults with CP during a full range of motion single degree of freedom task.
