University of Louisville researcher Claudia Angeli‘s recent paper details the process of electrical stimulation of the spinal cord enabling paralyzed patients to intentionally move their knees, ankles, and toes.

The stimulation therapy involves implanting a 16-electrode array in the epidural space next to the outermost protective layer of the spinal cord. The array is connected to a pulse generator resembling a pacemaker that’s implanted nearby. The pulse generator is controlled wirelessly by a programming device outside the body.

The array delivers electrical pulses to the spinal cord below the site of the injury, awakening the connections of that circuitry and getting it to function again. With the stimulation turned on, the four paralyzed men in the study were able to make voluntary leg, ankle, and toe movements on command.