News release

From: Springer Nature

Restoring hand movement and sensation after paralysis

A neuroprosthetic system has helped a man with paralysis to move his hand and feel touch again following a spinal cord injury, reports research published in Nature Medicine. Some of the benefits of the system were found to continue even when the device was turned off, which suggests that it may support longer-term recovery, as well as helping movement in real time.

Spinal cord injury is a leading cause of paralysis, and more than half of the cases involve tetraplegia, in which movement of the arms and legs is affected. Complete spinal cord injuries, in which there is no voluntary movement or feeling below the level of the injury, are particularly difficult to treat. Previous brain–computer interface systems have helped to restore some movement but have not yet restored a sense of touch or supported longer-term recovery.

Chad Bouton and colleagues developed a “double neural bypass” system, which reads brain signals linked to the person’s intention to move. It then uses these signals to help control a person’s own hand by delivering targeted stimulation to the spinal cord and the part of the brain involved in touch, the primary somatosensory cortex. In a clinical trial, this system was tested on a 42-year-old man with complete tetraplegia after a spinal cord injury. Stimulation of the spinal cord alone was found to improve his ability to bend his elbows, allowing him to bring both hands to his face. The full system also helped him to open and close his hand, drink from a cup, feed himself, and control his grip when handling delicate objects. The system continued to recognise the participant’s intended hand movements for more than 5 months, without needing repeated retraining. The participant also gained some touch sensitivity in his wrist, which persisted for more than 2 months after stimulation had stopped.

The authors suggest that this approach could help restore useful hand movement and touch after severe paralysis. However, further testing in more people with different injuries is needed. The system is also still highly specialised and currently needs trained staff to operate it.