Intraspinal Stimulation Could Re-Animate Paralyzed Arms and Hands
Researchers at the Center for Sensorimotor Neural Engineering (CSNE), an NSF-funded Engineering Research Center (ERC) with headquarters at the University of Washington, have demonstrated several powerful effects of stimulation within the spinal cord that may have important impacts on the treatment of spinal cord injury.
Intraspinal microstimulation (ISMS) may be an ideal method for re-animation of paralyzed hands and arms for individuals who have suffered spinal cord injury or stroke. CSNE hopes to develop a system in which stimulation is controlled by the intention to move, as transmitted by electrodes placed on or in the brain. Such a complete, closed-loop system would be a transformative treatment for paralyzed individuals.
Stimulation within the neck region of the spinal cord is capable of evoking a wide range of hand and arm movements, even after an intervening spinal cord injury. In addition, spinal stimulation led to persistently improved forelimb function in animals with chronic spinal cord injury, even after the stimulation was discontinued.
The application of intraspinal microstimulation, delivered at a precise time after activity is recorded in the brain, can robustly influence the connections between these distant regions. The final experiments were enabled by customized, onboard electronics developed in collaboration with electrical engineers and demonstrate the synergy of hardware and neuroscience enabled by the CSNE.
Intraspinal stimulation may be the ideal output for a brain/computer interface for several reasons. First, activating neurons within the spinal cord produces fatigue-resistant contractions and with lower currents, compared to muscle stimulation. Second, functional reach and grasp movements are evoked from single stimulating locations, reducing the total number of stimulating channels and associated controller complexity. Finally, most signals can remain inside the body, reducing the bandwidth of wireless transmission and overall power requirements for the implanted device.