Robotic Neuromuscular Facilitation for Regaining Neural Activation in Hemiparetic Limbs

This paper introduces an effective engineered rehabilitation system for understanding and inducing functional recovery of hemiparetic limbs based on the concept of timing-dependent induction of neural plasticity. Limb motor function is commonly impaired after neurologic injury such as stroke, with hemiparesis being one of the major impairments. In an emerging unique intervention for hemiparesis, named repetitive facilitation exercise, or RFE, a therapist manually applies brief mechanical stimuli to the peripheral target muscles (e.g., tapping, stretching of tendon/muscle) immediately before a patient intends to produce a movement with the muscle. The practice of this rehabilitation procedure by a skilled therapist often leads to dramatic rehabilitation outcomes. However, unskilled therapists, most likely due to the inaccuracy of the timing of peripheral stimulation in reference to the intention of movement (i.e. motor command), are unable to recreate the same rehabilitation results. Robotic rehabilitation, on the other hand, can improve the reliability and efficacy of the operation by satisfying the timing precision required by the therapy. This study demonstrates the use of a pneumatically-driven MRI-compatible robot for RFE assessment. The pressure dynamics of the system is studied for an accurate estimation on the time of response of the robot. The required temporal precision of the therapy is obtained and the use of the device is validated through experiments on a human subject.