PROJECT SUMMARY
Stroke is the 5th leading cause of death in the United States, and nearly 8 million Americans report it as their
primary reason for disability. For many with hemiparesis caused by their stroke, existing rehabilitative therapies
have failed to deliver sustained improvements in functional recovery. These therapies either focus on only the
impaired limb or rely on training tasks with little resemblance to activities of daily living. Emerging research
suggests that bilateral training may provide improvements beyond unilateral training alone, but the mechanisms
underlying these benefits remain unknown. Therefore, the objective of this proposal is to determine the motor
control and neuromuscular mechanisms responsible for bilateral coordinated reaching in stroke. To do this, we
have developed a rehabilitation platform that uses virtual reality and exoskeleton technologies to provide the
task and environmental constraints necessary to increase the use of the paretic limb in chronic stroke survivors.
Our preliminary results in healthy controls and 4 stroke participants show that our system can change both the
kinematic and neuromuscular control of upper extremity reaching. Our overarching hypothesis is that hemiplegic
stroke participants respond these novel task and environmental constraints by adopting an optimal reaching
strategy that manifests as systematic changes in impaired arm displacement and muscle activity. Specifically, in
Aim 1 we will explore the tradeoff between arm displacement and muscle activity during a bimanual reaching
task and in Aim 2, we will establish a neuromuscular mechanism of impaired limb recruitment during this task.
Specifically, we use an advanced electromyographical technique to measure coactivation of homologous muscle
pairs. Together, these two Aims will identify the kinematic and neuromuscular mechanisms responsible for
functional changes in bilateral coordination in chronic stroke survivors. The proposed research is supported by
a well-established mentorship team the spans clinical neurology, rehabilitation sciences, and biomedical
engineering. The work will be carried out in a unique collaboration between Georgetown University, the MedStar
National Rehabilitation Hospital, and The Catholic University of America. These institutions are perfectly
integrated to provide the clinical, technical, and intellectual environment needed to complete the proposed work.
Training will include mentored clinical experience with acute and chronic stroke survivors and train the applicant
in advanced engineering approaches to stroke rehabilitation. Finally, the training plan is designed to transition
the applicant into an independent research career focused on exploring the next generation of technological
solutions to therapeutic challenges.
