Imagine having to feed yourself without the ability to move your own arms. For Jan Scheuermann, a paraplegic, this is a task she is faced with everyday. A team of researchers from the University of Pittsburgh School of Medicine and UPMC worked with Ms. Scheuermann to once again give her the ability to feed herself. They proved that a person with longstanding quadriplegia can use a mind-controlled robot arm to perform many of the natural motions of everyday life.
According to UPMC, Ms. Scheuermann told the researchers less than one year ago that she was going to feed herself chocolate before the conclusion of the study. “One small nibble for a woman, one giant bite for BCI [brain-computer interface technology],” she said after accomplishing her goal.
“This is a spectacular leap toward greater function and independence for people who are unable to move their own arms,” said Andrew B. Schwartz, a professor in the Department of Neurobiology at the Pitt School of Medicine, in a statement. “This technology, which interprets brain signals to guide a robot arm, has enormous potential that we are continuing to explore. Our study has shown us that it is technically feasible to restore ability; the participants have told us that BCI gives them hope for the future.”
In 1998, Ms. Scheuermann was diagnosed with pinocerebellar degeneration, a condition in which the connections between the brain and muscles slowly, and for reasons still not known to scientists, deteriorate.
“Now I can’t move my arms and legs at all. I can’t even shrug my shoulders,” she said at the time. “But I have come to the conclusion that worrying about something is experiencing it twice. I try to dwell on the good things that I have.”
Ms. Scheuermann was motivated to do something about her condition after a friend showed her an October 2011 video about another Pitt/UPMC BCI research study in which Tim Hemmes, a man with quadriplegia, was able to reach out with a robot arm and touch his girlfriend.
“Wow, it’s so neat that he can do that,” Ms. Scheuermann said after seeing the video. “I wish I could do something like that.”
On February 10, 2012, UPMC neurosurgeon Elizabeth Tyler-Kabara placed two quarter-inch square electrode grids with 96 small contact points each in the regions of Ms. Scheuermann’s brain that would normally control right arm and hand movement.
“Prior to surgery, we conducted functional imaging tests of the brain to determine exactly where to put the two grids,” Ms. Tyler-Kabara said. “Then we used imaging technology in the operating room to guide placement of the grids, which have points that penetrate the brain’s surface by about one-sixteenth of an inch.”
The electrode points pick up signals from individual neurons and computer algorithms are used to determine the firing patterns linked to particular observed or imagined movements, such as raising or lowering the arm. That intent to move is then translated into actual movement of the robot arm.
After the operation, researchers connected the two terminals that protrude from Ms. Scheuermann’s head to the computer.
“We could actually see the neurons fire on the computer screen when she thought about closing her hand,” said lead investigator Jennifer Collinger, an assistant professor in the Department of Physical Medicine and Rehabilitation and research scientist for the VA Pittsburgh Healthcare System, in a statement. “When she stopped, they stopped firing. So we thought, ‘This is really going to work.’”
According to UPMC, Ms. Scheuermann had 3-dimensional control of the robot arm within a week. Within three months, the woman could also flex the wrist back and forth, move it from side to side and rotate it clockwise and counter-clockwise. She could also grip objects. All of this, researchers say, added up to 7D control of the robot arm.
“Our findings indicate that by a variety of measures, she was able to improve her performance consistently over many days,” Mr. Schwartz said. “The training methods and algorithms that we used in monkey models of this technology also worked for Jan, suggesting that it’s possible for people with long-term paralysis to recover natural, intuitive command signals to orient a prosthetic hand and arm to allow meaningful interaction with the environment.”
Researchers contend that the next step for BCI technology will utilize a two-way electrode system than can not only detect the intention to move, but will stimulate the brain to generate sensation, giving a user the ability to grasp something firmly or hold something carefully.
“We’re hoping this can become a fully implanted, wireless system that people can actually use in their homes without our supervision,” Ms. Collinger said. “It might even be possible to combine brain control with a device that directly stimulates muscles to restore movement of the individual’s own limb.”
The study’s findings were recently published in the online version of the journal The Lancet.