In the current investigation, Dr Angeli and her colleagues placed a 16-electrode array into the epidural space spanning the first lumbar vertebrae to the first or second sacral vertebrae; this was below each patient’s injury and encompassing the spinal cord regions that transmit signals to the legs. The stimulator control and battery were implanted into the abdominal wall, allowing for wireless remote control of the system.
After several weeks of testing to determine which combinations of electrodes were best suited to different leg and hip muscle movements, the grueling training regimen began. The four participants met with the researchers for two hours a day, five days a week, practicing mentally focusing on a particular movement while the corresponding stimulation pattern was active. Following 147 sessions, Thomas was able to walk on her own with a walker and stand for up to 50 minutes. Marquis, whose injury had been more severe, achieved independent walking with poles for balance after 278 sessions.
As of now, the participants’ regained movements are only possible when the electrodes are powered on. However, an earlier epidural stimulation patient under lead author Susan Harkema’s care was able to regain movement abilities without stimulation following more than 3.5 years of nervous system training.
“We must expand this research – hopefully, with improved stimulator technology – to more participants to realize the full potential of the progress we’re seeing in the lab, as the potential this provides for the 1.2 million people living with paralysis from a spinal cord injury is tremendous,” Harkema said in a statement.