THURSDAY, July 9, 2009 (HealthDay News) -- Microelectrodes that sit on, instead of in, the brain may one day help paralyzed people move their limbs -- whether they are real or bionic appendages, according to researchers who have developed such a device.
The University of Utah research team, whose work is explored in the July 1 online edition of Neurosurgical Focus, hope their microelectrocorticography, or microECoG, devices also eventually allow people who have lost the power of speech to speak again via computer.
"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," researcher Bradley Greger, an assistant professor of bioengineering, said in a news release issued by the university. "That lets neurosurgeons put this device under the skull but over brain areas where it would be risky to place penetrating electrodes: areas that control speech, memory and other cognitive functions."
In an experiment involving two people with severe epilepsy, the microECoG array successfully picked up brain signals so that the participants could accurately move their arms as directed. After a craniotomy, the grid-like array on a thin layer of silicone was laid directly on the sections of the brain responsible for arm and hand movements. Depending on the power and amplitude of the brain wave, the electrodes determined what direction the person wanted the arm to move.
"This device should allow a high level of control over a prosthetic limb or computer interface," Greger said. "It will enable amputees or people with severe paralysis to interact with their environment using a prosthetic arm or a computer interface that decodes signals from the brain."
Though similar but larger electrode arrays have been developed and used for the same purposes, their size and need for them to actually poke into the brain pose many risks and problems, the researchers noted. Having the microelectrodes just sit on the brain eases some of these concerns, they added.
University of Utah neurosurgeon Dr. Paul A. House, lead author of the report, said in the news release that he thought the experiment's success was "a modest step" forward. He noted that advances in software design, refinements in distinguishing brain waves and continued work into bionic limb technology would be necessary before use of microECoG became a complete reality for the injured.
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The University of Washington has more about how the brain works.
