Stroke-related paralysis: Spinal stimulation could help restore mobility

How can electric stimulations help?

In spinal cord stimulation, electrodes are placed on the surface of the spinal cord to deliver pulses of electricity to the nerves. These pulses activate the nerve cells of the spinal cord. The approach has previously been used to treat high-grade, persistent pain and restore leg movement after spinal cord injury.

However, the human arm is a complex system. The hands are dextrous, while the arm has a wide range of motion. The neural signals needed to control them add further complexity to the mix. The researchers used computer modeling and conducted preclinical testing in macaque monkeys before being authorized to optimize human therapy.

In a series of tests adapted to the needs of the patients, the stimulation enabled patients to perform tasks of different complexities, whether it was moving objects, opening a lock, or holding a can of soup. The electrodes allowed patients to open and close their fists fully, lift their arms above their heads, and even use a fork and knife to eat.

“By stimulating these sensory nerves, we can amplify the activity of muscles that have been weakened by a stroke," said Douglas Weber, a professor of mechanical engineering at the Neuroscience Institute at Carnegie Mellon University. "Importantly, the patient retains full control of their movements: The stimulation is assistive and strengthens muscle activation only when patients are trying to move.”

Interestingly, the effect of the stimulation lasted even after the device was removed. Researchers have therefore concluded that it can be used as an assistive and restorative method for recovery of the upper limb.

The researchers now plan to enroll further participants to optimize the treatment based on the severity of the condition. The research findings were published today in the journal, Nature Medicine.