Electrodes offer amputees, paralyzed people new hope

Spencer Kellis headed into his doctoral program at the University of Utah thinking he'd be using computers to perform architectural analysis, but over a lunch with researchers last summer, his focus changed.

The result now has the potential of changing lives.

"The human interaction and human aspect provides more motivation," the electrical engineering student said Monday. "It makes it easier to crunch numbers knowing that there are people who will benefit from the research we do."

Kellis was one of a number of students, researchers and others involved in a new study revealing that amputees and paralyzed people can do without brain poking to move various parts of their body. Kellis was responsible for generating preliminary graphs used to make conclusions on how brain signals power the rest of the human body.

Electrode arrays were placed on the brains of two patients at the U. hospital who were already undergoing brain surgery for severe epilepsy. The trials revealed optimal spacing of the electrodes and allowed researchers to further help in movement of immobile limbs.

Until now, such patients have used computers connected to electrodes within the brain, and other experimental devices to control bionic limbs and prosthetics. The study, published Tuesday in the journal Neurological Focus, shows that brain signals controlling arm movements can be detected accurately using new microelectrodes that sit on the brain but don't penetrate it.

"The unique thing about this technology is that it provides lots of information out of the brain without having to put the electrodes into the brain," said Bradley Greger, an assistant professor of bioengineering at the U. and co-author of the study. "That lets neurosurgeons put this device under the skull but over brain areas where it would be risky to place penetrating electrodes such as areas that control speech, memory and other cognitive functions."

Paralyzed people with an inability to communicate may someday benefit from the findings, allowing the electrodes surrounding the brain to send signals to a computer that would convert the thoughts to audible words. The same would be true for people who have lost a limb or complete function of their arms or legs, as the new device would give them a broader range of control over a prosthetic or computer interface, enabling "amputees or people with severe paralysis to interact with their environment," Greger said.

U. neurosurgeon Paul A. House, the study's lead author, said the new research represents "a modest step" in assisting people with disabilities.