MRI-Compatible Stroke Rehabilitation Device Links Brain and Muscles
The repetitive facilitation exercise (RFE) is a common rehabilitation tactic for stroke patients attempting to regain wrist movement. Stroke hemiparesis individuals are not able to move that part of their body because they cannot create a strong enough neural signal that travels from the brain to the wrist. With RFE, patients are asked to think about moving and at the same time, a practitioner flexes the wrist. The goal is to send a long latency response from the stretch that arrives in the brain at the exact time the thought happens, creating a neural signal. The result is a strong, combined response that zips back to the forearm muscles and moves the wrist. "Timing is everything. It's not easy for two people to match each other," says Georgia Institute of Technology master's graduate Lauren Lacey. The Georgia Tech team has created a mechanical device that takes people out of the process, replacing them with accurate computers. Their functional MRI-compatible hemiparesis rehab device creates a long latency stretch reflex at the exact time as a brain signal. A pneumatic actuator tendon hammer hits a person's wrist while a transcranial magnetic stimulator creates a weak signal in the brain's motor cortex. Because the machine is MRI-compatible, it will allow the team to study what is happening in the brain during rehab, opening the door for robotics.