Brain Controlled Switches Coming
Source: University Of Rochester
http://www.sciencedaily.com/releases/2000/05/000503180714.h
tm
May 5, 2000
Glancing at a stereo and turning it on with a thought
may have
once been science fiction, but inside a virtual world at the
University of Rochester, people are listening to music by simply
wishing it so. Outfitted with a virtual reality helmet and a
computer program adept at recognizing key brain signals,
volunteers use their thoughts to take actions like those of any
apartment dweller-turning on the television or the stereo, for
instance. The line of research, which links a brain and computer
in a near real-world environment, may someday allow patients with
extreme paralysis to regain some control of their surroundings,
say the project's developers, and could eventually eliminate
keyboards and computer mice as the go-betweens connecting our
thoughts and the actions we wish to see in our environment.
While several teams around the world are working on
brain-computer interfaces (BCI), computer science graduate
student Jessica Bayliss is the first to show that detection of
the brain's weak electrical signals is possible in a busy
environment filled with activity. She has shown that volunteers
who don a virtual reality helmet in her lab can control elements
in a virtual world, including turning lights on and off and
bringing a mock-up of a car to a stop by thought alone.
Though all this is currently taking place only in
virtual reality, the team is confident that the technology will make
the jump to the "real world" and should soon enable people to look
around a real apartment and take control in a way they couldn't
before.
"This is a remarkable feat of engineering," says Dana
Ballard, professor of computer science and Bayliss' adviser. "She's
managed to separate out the tiny brain signals from all the electric
noise of the virtual reality gear. We usually try to read brain
signals in a pristine, quiet environment, but a real environment isn't
so quiet. Jessica has found a way to effectively cut through the
interference." The National Institutes of Health is supporting
Bayliss' research because it may someday give back some control to
those who have lost the ability to move. A person so paralyzed that he
or she is unable even to speak may be able to communicate once again
if this technology can be perfected, explains Bayliss. By merely
looking at the telephone, television or thermostat and wishing it to
be used, a person with disabilities could call a friend or turn up the
heat on a chilly day. Bayliss hopes that someday such people may even
be able to operate a wheelchair by themselves simply by thinking their
commands.
"Virtual reality is a safe testing ground," says
Bayliss. "We can see what works and what doesn't without the danger of
driving a wheelchair into a wall. We can learn how brain interfaces
will work in the real world, instead of how they work when someone is
just looking at test patterns and letters. The brain normally
interacts with a 3-D world, so I want to see if it gives off different
signals when dealing with a 3-D world than with a chart."
The brain signal Bayliss listens for is called the "P300
evoked potential." It's not a specific signal that could be translated
as "Aunt Nora" or "stop at the red light," but rather a sign of
recognition-more like "That's it!"
"It's as if each neuron is a single person who's
talking," explains Bayliss. "If there's just one person, then it's
easy to hear what he's saying, but the brain has billions of neurons,
so imagine a room full of a billion people all talking at once. You
can't pick out one person's voice, but if everyone suddenly cheers or
oohs or aahs, you can hear it. That's what we listen for, when several
neurons suddenly say 'that's it!' "
Bayliss looks for this signal to occur in sync with a
light flashing on the television or stereo. If the rhythm matches the
blinks of the stereo light, for instance, the computer knows the
person is concentrating on the stereo and turns it on. A person
doesn't even have to look directly at the stereo; as long as the
object is in the field of view, it can be controlled by the person's
brain signals. Since it's not necessary to move even the eyes, this
system could work for paralysis patients who are completely "locked
in," a state where even eye blinks or movement are impossible.
The virtual apartment in which volunteers have been
turning appliances on and off is modeled after Bayliss' own. Such a
simple, virtual world is the first step toward developing a way to
accurately control the real world. Once Bayliss has perfected the
computer's ability to determine what a person is looking at in the
virtual room, the next hurdle will be to devise a system that can tell
what object a person is looking at in the real world. BCI groups are
also close to surmounting another obstacle-that of attaching the
sensors to the head.
Right now dozens of electrodes must be attached to the
scalp one at a time with a gooey gel, but Bayliss says dry sensors are
just around the corner, and simple slip-on head caps should not be far
behind.
"One place such an interface may be very useful is in
wearable computers," Ballard says. "With the roving eye as a mouse and
the P300 wave as a mouse-click, small computers that you wear as
glasses may be more promising than ever."
BCIs are divided into two categories: biofeedback and
stimulus-response. Bayliss uses the latter approach, which simply
measures the response the brain has to an event. Biofeedback is a
method where a person learns to control some aspect of his or her
body, such as relaxing, and the resulting change in the brain can be
detected. Though many BCI groups use this approach, Bayliss decided
against it because people must be trained, sometimes for a year or
more, and not everyone can learn to accurately control their thought
patterns.
Bayliss and Ballard work in the University's National
Resource Laboratory for the Study of Brain and Behavior, which brings
together computer scientists, cognitive scientists, visual scientists,
and neurologists to study neural functions in complex settings. The
laboratory's research combines tools that mimic real-world sensations,
such as virtual reality driving simulators and gloves that simulate
the feel of virtual objects, with sensory trackers that measure eye,
head, and finger movements. Recently the lab added virtual people,
robot-like actors with which volunteers can interact in a limited way.
So in the future will we all be wearing little caps that
will let us open doors, channel surf and drive the car on a whim? "Not
likely," Bayliss says. "Anything you can do with your brain can be
done a lot faster, cheaper and easier with a finger and a remote
control."
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