Sunday, February 27, 2011

Pitt to test brain implants in paralyzed patients

Pitt to test brain implants in paralyzed patients
Thursday, February 17, 2011
The University of Pittsburgh will become one of the few places in the world to test brain implants in paralyzed patients in hopes of training them to move prosthetic arms with their thoughts.
The experimental work, involving two different kinds of electrode implants in the brain, is designed to interpret patients' brain signals, route them through a computer, and then control the movement of a prosthetic arm and hand, with a movable wrist and fingers.
If the research is successful, it could lead to implants that would allow patients to stimulate and control their own paralyzed arms, said Michael Boninger, director of the UPMC Rehabilitation Institute and a senior scientist on both projects.
The patients have not yet been chosen, Dr. Boninger said, but will probably be people with quadriplegia whose paralyses were caused by accidents.
The experiments build on the world-renowned work of Andrew Schwartz, a Pitt neurobiology professor, who has implanted electrodes in monkeys that have allowed them to control increasingly sophisticated prosthetic arms.
The projects are getting nearly $7 million over the next three years from the National Institutes of Health and the Defense Advanced Research Projects Agency.
The smaller of the two experiments will put an array of 16 electrodes on the surface of the brain in three patients for a month to test the concept of using brain-wave readings to move a cursor on a computer screen and then manipulate a prosthetic arm.
The other experiment will implant two sets of 100 electrodes each in the motor cortex of three paralyzed patients, Dr. Schwartz said in an interview Wednesday. The first patient, who will get the implants this summer, will have two small pedestals on the surface of the skull, from which wires will relay brain signals to a computer and then to a prosthetic arm.
One pedestal will channel signals from electrodes placed in an area that controls the arm, and the other from electrodes that control the wrist and hand.
The first patient's implants are scheduled to stay in place for a year. In 2012, a second patient would get implants that would also allow the patient to sense the movement of the arm and hand through a feedback circuit to the brain, he said.
A third patient in 2013 would get implants that would transmit signals wirelessly to control two prosthetic arms. Dr. Schwartz said.
In both projects, the patients start by observing the prosthetic arm's movements while the electrodes monitor signals from the motor control portions of their brains. Computer software can then use those patterns of signals to move the arm in the direction that the patient wants.
The longer project involving the implanted electrodes is being led by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., which oversaw development of the prosthetic arms and accompanying technology.
Other participants include Blackrock Microsystems in Utah, which makes the brain electrodes, and the California Institute of Technology, which is scheduled to try a different kind of brain implant in a patient in the future.
From a practical standpoint, Dr. Schwartz said, "we want to make this [prosthetic] arm perform as close to a real arm and hand as we can. When you ask these [paralyzed] subjects what they really want, they say they want to be able to use their hands to feed themselves and maintain themselves and do their buttons and zippers."
At a deeper level, he said, the researchers are learning how the brain carries out its plans. "We're trying to understand how the brain learns by watching the neurons fire, and that is very exciting."

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