Brainwaves Can Control Movement In Paralyzed PeopleAug 8, 2005 | Ivanhoe Broadcast News Every year, about 11,000 Americans experience a spinal cord injury, adding up to 200,000 people living with spinal cord injury disability in the United States.
Spinal cord injury usually begins with a sudden, traumatic blow to the spine that fractures or dislocates vertebrae. Accidents -motor vehicle accidents, falls and sports injuries and acts of violence cause most injuries to the spinal cord. The damage begins at the moment of injury when displaced bone fragments, disc material, or ligaments bruise or tear into spinal cord tissue.
Most injuries to the spinal cord don't completely sever it. Instead, an injury is more likely to cause fractures and compression of the vertebrae, which then crush and destroy the axons, which are extensions of nerve cells that carry signals up and down the spinal cord between the brain and the rest of the body.
An injury to the spinal cord can damage a few, many, or almost all of these axons. Some injuries will allow almost complete recovery. Others will result in complete paralysis. Spinal cord injuries are classified as either complete or incomplete. An incomplete injury means that the ability of the spinal cord to convey messages to or from the brain is not completely lost. People with incomplete injuries retain some motor or sensory function below the injury. A complete injury is indicated by a total lack of sensory and motor function below the level of injury. People who survive a spinal cord injury will most likely have medical complications such as chronic pain and bladder and bowel dysfunction, along with an increased susceptibility to respiratory and heart problems.
There has been successful research in a number of fields that may someday help people with spinal cord injuries. Genetic studies have revealed a number of molecules that encourage axon growth in the developing central nervous system (CNS) but prevent it in the adult CNS. Research of embryonic and adult stem cell biology has furthered knowledge about how cells communicate with each other.
Other research, such as that conducted at the University of Washington, is revealing ways to help those paralyzed from spinal injuries use their minds to control computers, and potentially, prostheses. The first step is figuring out how to use brainwaves to control a computer program.
Jeffrey Ojemann, M.D., is an associate professor of neurological surgery. He said the electrical signal our brain sends out to move our hand is the same whether we actually move it or just imagine it. Using electrodes implanted in the skull and attached to the brain surface, that signal can be translated into a command for a computer or for a wheelchair to move.
"What's exciting about it is when people can't move their arms or legs, and all they need is a little bit of ability to communicate or a little bit of help [to control something], this offers them a potential way that they can do that," Ojemann said.
He adds that although the strongest signal is generated when patients actually move, they are able to get a signal when patients are simply thinking. Right now, research is being done on epilepsy patients who already have electrodes in place to help them control seizures.