The study included 4 men, average age 26.9 years, with a spinal cord injury incurred at least 2 years before the study. Their injuries ranged in neurologic level from C7 to T5. None were able to stand or walk independently or voluntarily move their lower extremities despite standard-of-care rehabilitation and additional intense locomotor training.
Researchers implanted a stimulator into the abdomen of each patient. The stimulator was originally developed for use in pain but was refined for use as an epidural spinal cord stimulator.
The investigators also implanted a 16-electrode array over vertebrae T11 to T12, where the locomotor sensors are located, said Dr. Angeli. The electrodes were placed in the same location in all patients, regardless of the location of their injury.
Each patient had an individually programmed device that they simply placed over the abdomen to initiate stimulation. There was a separate program for the left and for the right leg.
With stimulation and with auditory and visual cues, the patients could execute intentional movements of the legs. Dr. Angeli emphasized that such movements required "very precise motor control."