A device that was implanted in a man's brain has restored his feelings of touch, according to a new study. This is the first time such a device has been used to restore a sense of touch in a person with a spinal cord injury, the researchers said.
The patient, although paralyzed by his injury, could experience the sensations through a mind-controlled robotic armconnected directly to his brain, the researchers said.
The man, Nathan Copeland, lives in western Pennsylvania. In the winter of 2004, he was driving at night in rainy weather and was in a car crash that snapped his neck and injured his spinal cord. The crash left Copeland, then 18, with quadriplegia from the upper chest down. He was unable to feel or move his legs or lower arms, and needed assistance with all of his daily activities.
"I don't have any finger movement, or thumbs - just kind of have fists, which I still get along with," Copeland said. "I can still type. I type with the knuckles of my pinkies."
At the time of the crash, Copeland was in his first year of college, pursuing a degree in nanofabrication. But health problems forced him to put his degree on hold. After the car crash, he enrolled in a registry of patients willing to participate in clinical trials.
In the spring of 2015, Copeland had two electronic chips, each about half the size of a shirt button, implanted into a part of his brain called the somatosensory cortex, which controls touch, including in the hands. Each chip had an array of 32 needle-like electrodes about 2 microns wide, or about one-fiftieth the diameter of the average human hair, developed by Blackrock Microsystems in Salt Lake City. These electrodes could electrically stimulate neurons in his brain to recreate his perception of touch while bypassing his spinal cord injury.
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"To date, all attempts to restore sensations of touch through brain implants have either been done in animal experiments or have used very large electrodes during existing operations," said Robert Gaunt, a senior author of the study and a neuroengineering researcher at the University of Pittsburgh.
Previous research using this new technique with much smaller electrodes, known as intracortical microstimulation, had looked promising in studies on animals. However, it was uncertain whether the artificial sensations would feel natural to a person.
Researchers have learned about human sensations from brain surgeries done with the patient awake, in which "they stimulate the brain and ask people what they feel," Gaunt told Live Science. But typically, the electrodes used in those surgeries are 1,000 times larger than the electrodes the researchers used in Copeland's implants, Gaunt said. "These large electrodes generate buzzing sensations that come from large areas of skin, typically - for example, the whole hand," he said. "It does not feel normal."
In other work, researchers have restored sensations of touch in the arms of people with amputations by stimulating nerves in the remaining parts of their arms. However, such work could not help restore touch in people with spinal cord injuries, who have damage in the central nervous system, Gaunt said.
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