Spinal nerve cell stimulation restores movement for stroke patients

Scientists from the University of Pittsburgh and Carnegie Mellon University in the US have found a way to restore arm and hand control in stroke patients. By stimulating nerve cells inside the spinal cord, the team improved the range of movement for two participants with chronic post-stroke upper-limb weakness.

Around one in four people across the world will have a stroke in their lifetime. After the blood supply has been cut off from the brain, stroke survivors can experience a number of long-term conditions. Common among them are issues to do with moving the hands and arms, which can have a serious impact on independent living.

The American researchers noted that the connections between the brain and regions of the spinal cord that are responsible for controlling arm and hand movements are often disrupted after a stroke. It can leave the signals too weak to enable activity in the muscles, which was an area they set out to explore.

By stimulating the sensory neurons of the muscles that communicate with the motor neurons of the arm, the scientists believed they may be able to restore movement. They did this by implanting electrode arrays into the two study participants.

This minimally-invasive approach was carried out with a needle and saw the array, which resembles a noodle, positioned on top of the point where the sensory nerves from the arm enter the spinal cord. They were left in situ for 29 days and testing began four days after the electrodes were put in place.

Over the course of four weeks, tests were carried out for four hours a day, five days a week to determine the impact of the stimulation. Arm and hand strength was found to improve when the electrodes were switched on and the participants enjoyed a greater range of movements.

Heather Rendulic, one of the participants in the study, said: “Stimulation feels kind of like a tickle and it’s never painful, but it takes some getting used to, I would say. It’s just awesome because I can move my arm and hand in ways that I haven’t done in almost a decade.”

Among the tasks the two individuals completed, which would usually be beyond their capabilities, were eating with a fork and opening a lock. By the end of the study, both participants were demonstrating some lasting improvements in motor function even when the stimulation wasn’t switched on.

Photo credit: Unsplash/Travis Yewell