Implantation of electrodes helps with paralysis
Researchers at the University of California, the California Institute of Technology and the University of Louisiana, working under the guidance of Professors Victor Reggie Edgerton and Susan Harkema, by implanting a complex of stimulating electrodes, returned to a paralyzed man the ability to stand, walk with support on a treadmill and make arbitrary movements with his limbs. Electrostimulation activates its own neural network of an intact part of the spinal cord, which allows using signals coming from sensitive neurons of the legs to control the movements of muscles and joints.
The work is based on the results of a series of experiments started by specialists of the University of California back in the 80s. These experiments have shown that epidural stimulation (performed from the outside of the uppermost of the three membranes of the spinal cord and brain) allows animals with spinal cord injuries to stand, support the weight of the trunk, maintain balance, and take directed steps.
The final result of this and later studies was the development of a complex of electrodes for epidural stimulation suitable for clinical studies.
The first participant in the study was a 23-year-old former athlete Rob Summers, who was completely paralyzed from the chest down after being hit by a car in 2006, hiding in an unknown direction.
Before implantation of the electrodes, the patient, who completely lost the mobility of his legs, but partially retained their sensitivity, received 170 sessions of rehabilitation training that had no effect, which confirmed the severity of the damage.
After implantation of the device and several weeks of training on a treadmill during electrical stimulation, the patient can stand up on his own and hold his weight in an upright position for 20 minutes.
With the help of seat belts and a physiotherapist, he can walk on a treadmill. Daily workouts and electrical stimulation restored the patient's ability to move his toes, as well as ankle, knee and hip joints arbitrarily (three short videos can be viewed on the Technology Review website).
An unexpected side effect of the procedure was the improvement of arbitrary control of excretory functions of the bladder and intestines.
To date, experts do not fully understand how electrical stimulation ensures the restoration of damaged or the formation of new interneuronal contacts. They believe that the reorganization of the neural pathways occurs below, and possibly above, the site of injury.
The researchers received permission from the U.S. Food and Drug Administration to conduct studies involving five patients. Its next participant should be a patient with similar physical characteristics and the nature of the injury. This will confirm the validity of the results. Subsequently, the device will be implanted in patients who have completely lost the sensitivity of the lower extremities.
Currently, scientists are working on optimizing electrical stimulation models and improving the design of the electrode complex. They hope that in the future, patients who have lost mobility as a result of spinal cord injuries, as well as, possibly, stroke and other disorders of motor function, will be able to move with the help of portable electrical stimulators.
Article by Susan Harkema et al. Effect of epidural stimulation of the lumbosacral spinal cord on voluntary movement, standing, and assisted stepping after motor complete paraplegia: a case study published May 20 in The Lancet.
Evgeniya Ryabtseva
Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of the California Institute of Technology:
Caltech Research Helps Paraplegic Man Stand and Move Legs Voluntarily.
23.05.2011