Imagine that a paraplegic, with just a simple thought, is able to control his or her wheelchair and send it in any direction without assistance from anyone else.

With a concentrated glance at a computer screen, the person in the wheelchair can direct the machine down a hallway and around obstacles as he or she makes his or her way to class or a meeting. A couple of hours later, with a mental command to the onboard computer, that same person can put the chair on “autopilot” and enjoy a casual stroll through a park with a friend.

The concept of brain-computer interface (BCI)—harnessing brainwaves to control external devices remotely with a computer serving as intermediary—is usually reserved for science fiction. But a team of California State University, Northridge researchers is making it a reality, and in the process hoping to provide a new level of independence to those with physical and cognitive disabilities.

Mechanical engineering professor C.T. Lin and seven graduate and undergraduate students from Northridge’s College of Engineering and Computer Science have spent the past year working on an ambitious BCI project designed to make movement easier for people in wheelchairs.

They already have a functioning prototype and plan to spend the next several months working out the kinks. At the end of that period, Lin expects to have a model ready for manufacture.

“That’s what we do, what engineering is all about—finding solutions to problems to benefit the greater community,” Lin said. “In this instance, we have created a solution for an important segment of our community, people with disabilities.”

The goal is to help people with physical impairments move around more easily in dynamically changing environments—whether they are navigating a crowded corridor on the way to class or strolling through the park with friends.

“This wheelchair gives them the ability to control where they go by themselves. It’s a level of independence many people in wheelchairs do not have yet,” he said.

Earlier this year, Cal State Northridge launched a new master’s degree in assistive technology and Lin is heading the engineering component. The new program builds on the university’s international reputation as a leader when it comes to meeting the needs of persons with disabilities. In addition to the extensive services the university provides to accommodate students with disabilities on campus, CSUN is home to the acclaimed National Center on Deafness and sponsors the annual International Technology and Persons with Disabilities Conference. The 26-year-old conference is the largest gathering of its kind, drawing thousands of people from around the world interested in exploring new ways assistive technology can make life better for persons with disabilities.

Enhancing independent mobility

Project member Lee Hern, a graduate student in computer science who uses a wheelchair, appreciates how liberating the BCI wheelchair could be to someone dependent on others to help them get around.

“Having grown up in an environment where the manual wheelchair is the only option, if you get into a situation where your mobility is limited, it’s extremely frustrating,” Hern said. “I can only imagine what it’s like for those who have to depend on others to help them get around. We want to give those people a chance to move about on their own.”

Alan Shewmon, a neurologist at Olive View-UCLA Medical Center in Sylmar, called the project “exciting.”

“This is a pilot project but it’s proof that this concept—that brain activity can be transformed into commands to govern a wheelchair—can be turned into a reality,” said Shewmon, who has consulted on the project.

In addition to Lin, Hern and Shewmon, the research team includes mechanical engineering graduate students Craig Euler, Alfie Gil and Yunsong Shen, electrical and computer engineering senior David Prince and mechanical engineering seniors Ara Mekhtarian and Joseph Horvath.

Their prototype is a modified motorized wheelchair outfitted with a laser sensor about a foot from the ground, a stereo camera mounted on a frame over the chair’s occupant, a laptop computer and an EEG headset designed to read the occupant’s brainwaves.

The sensor and camera continually scan the areas in front and about 270 degrees around the wheelchair and send the data to the onboard computer, which processes the information, noting any obstacles—from the legs of a table or chair to a person standing in the way—that may exist and any openings that can accommodate the wheelchair. The EEG headset sends the wheelchair user’s brainwaves—which are focused on such commands as forward, back, right or left—to the computer.

The computer is programmed to process the data from both sets of commands—one created by the user and the other generated by a sensor-based analysis by the onboard computer.

The wheelchair can then run in autonomous mode, where the computer makes all the decisions, or in hybrid mode, where the commands from the user are augmented by sensor analysis. The hybrid mode was created, in part, to help those who may have some visual or cognitive impairment that would interfere with their ability to see everything in their path.

“It will be up to the user to decide which one they want,” Lin said. “Concentrating is hard work, so the person in the wheelchair may want to do a combination of both, starting out with the hybrid mode as he or she makes their way through a crowd down a corridor to class. But once they are on a clear path, they may decide to switch over to the autonomous mode so they can relax and enjoy the company of the people they are with and the walk.”

Lin said training people to use the wheelchair only takes a few days while the onboard computer’s software learns to adapt to the EEG headset wearer.

“Each person is unique so the software is designed to gather data and continue to adapt to the person who is using the wheelchair,” he said. “The machine is always learning.”

Technology informed by personal experience

Hern, who is focused on improving the responsiveness of the EEG headset and its interface with the onboard computer, said his unique experience as a wheelchair user helps add a dose of “reality” to the project.

“I’m working with a bunch of engineers who are really good at building things, but they don’t always see the big picture,” he said. “They may not see things that someone in a wheelchair might see and realize they need.”

Among his suggestions: the BCI wheelchair needs to be able to adapt as its owner becomes more experienced using it. “For example, with a novice user, the chair might be limited to a quarter of its speed and have a safety margin much greater than somebody with more experience in using it,” he said.

As with any piece of equipment that gets used by one person over and over again, Hern said, a BCI wheelchair owner will eventually “become one” with his or her chair and will know its individual capabilities in many ways better than its creators.

“We need to be able to accommodate that,” he said.

Team member Craig Euler called Hern’s input “invaluable.” “It’s been amazing what he’s been able to do with the headset and bring to the table with his own personal experiences.”

Euler, who is focused on designing the software to ensure that the cognitive components of the wheelchair work well together, said his experiences with the BCI wheelchair have sparked an interest in exploring other projects in the burgeoning field of assistive technology.

“What we may be able to accomplish with this project—give someone a level of independence they never had before—is very cool,” Euler said.

— Carmen Ramos Chandler

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