In a small study, researchers used a device that stimulates the spinal cord to restore arm and hand mobility in two stroke patients, allowing them to perform daily life activities, such as using a fork to eat a meal. The study, published in Nature Medicine, was funded by the National Institutes of Health’s Brain Research Through Advancing Innovative Neurotechnologies®(BRAIN) Initiative.
The technology uses a set of thin metal electrodes implanted on the surface of the spinal cord. Electrical impulses from the device stimulate neural circuits in the spinal cord, priming them to receive movement signals from the brain. This engages muscles weakened by stroke, allowing patients to voluntarily lift their arm, open and close their fist, and grasp household objects.
Recent studies have used spinal cord stimulation technology to treat chronic pain and restore leg movement after spinal cord injury. Building on years of extensive preclinical studies using computer modeling and non-human primates, and a pilot study in humans, researchers tested the new therapy in two stroke patients with moderate to severe motor impairments.
They found that continuous stimulation targeting the cervical sensory nerve roots of the spinal cord immediately improved strength, range of motion, and arm and hand function. Stimulation also enabled participants to perform complex tasks requiring more skill and dexterity, such as using utensils to eat and opening a lock, which they had not done in years.
Surprisingly, some benefits persisted for several weeks after the device was removed. This suggests that this assistive stimulation approach could lead to more robust long-term improvements in motor function when combined with physical or occupational therapy.
Globally, one in four people over age 25 will suffer from a stroke, and nearly three-quarters of these individuals will have lasting deficits in the motor control of their arm and hand, causing disability and enormous impacts on daily life. There are no effective treatments for paralysis in the chronic stage of stroke, which begins six months after the initial stroke incident.
These findings provide a practical stimulation protocol for adapting an existing clinical technology to treat upper-limb paralysis following stroke. More research is needed to translate the therapy into broader clinical use. Future studies will examine ways to further optimize stimulation protocols and determine which stroke patients can benefit most from the therapy.