A surgically implanted nerve stimulation device, coupled with months of intensive training, has enabled two individuals with paralysis from traumatic injuries to walk independently years after losing all voluntary muscle control below the site of their spinal cord damage.
The details of this breakthrough "epidural stimulation" protocol – developed by teams from the Frazier Rehabilitation Institute and the University of Louisville Kentucky Spinal Cord Injury Research Center – were published today in the New England Journal of Medicine.
“It is incredible to be able to be in there and actually see them taking their first steps,” first author Dr Claudia Angeli told the Guardian. “It is an emotional time for the individual [themselves] because it is something that they have been told they are never going to be able to do again.”
Prior to their inclusion in the study, participants Kelly Thomas and Jeff Marquis had undergone conventional rehabilitation therapy for spinal cord injuries sustained in car and bike accidents, respectively, but remained unable to walk. Thomas had full use of her arms and Marquis had partial arm control, and both had retained slight sensation in their lower bodies.
Two other participants, also paraplegics but with no sensation below their injury sites prior to the investigation, were not able to walk without assistance after training with the device, yet they were able to stand and move their legs.
Though this treatment approach is still in its early days, these results further demonstrate that the framework of nerve connections necessary for voluntary movement is not completely destroyed by spinal cord trauma. Past research by the University of Louisville and other groups have shown that both implanted and subcutaneously applied electrodes can act as a bridge over the site of damage, connecting signals from the brain to the peripheral nerves that trigger muscles to contract. In recent human pilot studies, such devices have succeeded in restoring hand control in people with partial paralysis and leg movement in people with complete paralysis.