April 8, 2014
Spinal Stimulation Reactivates Paralyzed Limbs
[ Watch the Video: Voluntary Training With Spinal Stimulation ]
Brett Smith for redOrbit.com - Your Universe Online
A preliminary study from National Institutes of Health has found that people with paraplegia were able to voluntarily move previously paralyzed toes, ankles and knees while receiving electrical stimulation to the spinal cord.
The study team, who published their results in the journal Brain on Tuesday, said their discovery offers new hope to individuals who have been coping with paralysis for years.
"When we first learned that a patient had regained voluntary control as a result of spinal stimulation, we were cautiously optimistic," said Dr. Roderic Pettigrew, director of the National Institute of Biomedical Imaging and Bioengineering (NIBIB) at NIH. "Now that spinal stimulation has been successful in 4 out of 4 patients, there is evidence to suggest that a large cohort of individuals, previously with little realistic hope of any meaningful recovery from spinal cord injury, may benefit from this intervention."
The new research builds on a May 2011 study published in the journal The Lancet that examined the effects of epidural stimulation on Rob Summers of Portland, Ore., who recovered some motor function in response to the treatment. Summers’ treatment involved implanting a 16-electrode array on his spinal cord. He also underwent daily training to help him to either stand or walk. During these sessions, the array sent electrical pulses to his spinal cord just below his injury.
The new study involved three more patients with paralysis – two with total motor and sensory paralysis, and one like Summers, with motor paralysis but able to experience sensation below his injury. After just a few days of stimulation, all three patients reestablished limited voluntary control of previously paralyzed body parts.
The first person implanted after Summers could not move or experience any sensation below his injury.
"What was astounding about him was that not only was there voluntary movement, but we saw it in the first week of stimulation. We then saw it in the next two patients as well," said study author Susan Harkema, director of rehabilitation research at the Kentucky Spinal Cord Injury Research Center at the University of Louisville.
The researchers found that all three new patients, like Summers, could synchronize actions with the motions of a wave presented on a computer screen, and three participants could alter the pressure at which they moved their leg, with respect to the level of three distinct auditory cues.
"The fact that the brain is able to take advantage of the few connections that may be remaining, and then process this complicated visual, auditory, and perceptual information, is pretty amazing,” said study author V. Reggie Edgerton, a UCLA professor of integrative biology and physiology. “It tells us that the information from the brain is getting to the right place in the spinal cord, so that the person can control, with fairly impressive accuracy, the nature of the movement.”
The researchers repeated the tests after months of spinal stimulation and motor training. Following the training, some volunteers were able to carry out voluntary movements with greater drive and with decreased stimulation, while others acquired enhanced movement reliability. Harkema said it's unclear if the improvement was a consequence of the training or as a result of snowballing effects of stimulation. The team said they expect to test this difference in their next study.
"With this study the investigators show that their findings about a motor complete patient regaining movement, reported three years ago in The Lancet, were not an anomaly," said Susan Howley, executive vice president for research at the Christopher & Dana Reeve Foundation, which helped fund the study. "The implications of this study for the entire field are quite profound and we can now envision a day where epidural stimulation might be part of a cocktail of therapies used to treat paralysis."
Image 2 (below): Left to right is Andrew Meas, Dustin Shillcox, Kent Stephenson and Rob Summers, the first four to undergo task-specific training with epidural stimulation at the Human Locomotion Research Center laboratory, Frazier Rehab Institute, as part of the University of Louisville's Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky. Credit: University of Louisville