Control of Voluntary and Involuntary Nerve Impulses for Hemiparesis Rehabilitation and MRI Study

In order for stroke victims to gain functional recovery of their hemiparetic limbs, facilitation techniques such as the repetitive facilitation exercise, or RFE, have been developed. Currently, there is a lack of understanding of the neural mechanisms associated with these types of facilitation techniques. To better understand the neural mechanisms associated with the RFE a functional magnetic resonance imaging (fMRI) study should be conducted. This paper presents initial experimental results testing the feasibility of implementing an fMRI-compatible actuator to facilitate a myotatic reflex in synchronization with the patient’s intention to move the hemiparetic limb. Preliminary data from a healthy individual demonstrated the feasibility of overlapping the long latency component of the afferent myotatic reflex with descending nerve impulses in a time window of 15ms. In addition, to implement the RFE into an fMRI-compatible device, a pneumatic actuation time delay due to long transmission line was evaluated. The results may be used for the assessment of the RFE using an fMRI-compatible robotic device in the future.