July 21, 2006

Brain-computer link allows paralyzed patient to manipulate devices by thought

A patient with a spinal cord injury was able, by thinking of moving his paralyzed limbs, to produce brain signals that were picked up by a sensor implanted in his brain. These signals were translated into electronic impulses that allowed him to control a computer cursor and manipulate mechanical devices. A report in the July 13 issue of Nature includes the first published findings from an ongoing clinical trial of the BrainGate System, the brain-computer interface device used by the patient that is in the early stages of clinical testing at the MGH, Spaulding Rehabilitation Hospital and other institutions.

"The broad question we addressed is whether it's possible for someone with paralysis to use brain activity to control an external device," says Leigh Hochberg, MD, PhD (right), a neurologist at the MGH, Spaulding and BWH and lead author of the Nature paper. "We're finding that, even years after spinal cord injury, the same signals that originally controlled a limb are available and can be utilized."

The BrainGate System consists of an internal sensor to detect brain cell activity and external processors that convert brain impulses into computerized signals. Two clinical trials are currently underway to evaluate its safety and feasibility for translating brain activity from patients with paralysis from several causes and patients with ALS. Among the accomplishments of the first participant in these trials was moving a computer cursor to open simulated e-mail, draw circular shapes and play simple video games. He also was able to open and close a prosthetic hand and use a robotic limb to grasp and move objects.

"We hope the knowledge gained from this work will allow the development of systems that provide improved communication and environmental control for people with paralysis and someday, when combined with neuromuscular stimulators, restore control over their limbs," says Hochberg. He is collaborating with researchers at Brown University, several academic health centers and Cyberkinetics Neurotechnology Systems, the company that manufactures the BrainGate System.