With Tiny Brain Implants, Just Thinking May Make It So
April 13, 2004
By ANDREW POLLACK
Can a machine read a person's mind? A medical device
company is about to find out.
The company, Cyberkinetics Inc., plans to implant a tiny
chip in the brains of five paralyzed people in an effort to
enable them to operate a computer by thought alone.
The Food and Drug Administration has given approval for a
clinical trial of the implants, according to the company.
The implants, part of what Cyberkinetics calls its
BrainGate system, could eventually help people with spinal
cord injuries, strokes, Lou Gehrig's disease or other
ailments to communicate better or even to operate lights
and other devices through a kind of neural remote control.
"You can substitute brain control for hand control,
basically," said Dr. John P. Donoghue, chairman of the
neuroscience department at Brown University and a founder
of Cyberkinetics, which hopes to begin the trial as early
as next month.
The melding of man and machine has long been a staple of
science fiction. Indeed, the participants in
Cyberkinetics's clinical trial, who have not yet been
chosen, will have a cable sticking out of their heads to
connect them to computers, making them look something like
characters in "The Matrix."
But in real life, several research groups have already
implanted devices in monkeys that allow them to control
cursors on computer screens or move robot arms using their
brainpower alone, setting the stage for the trial in
people.
"Among many people in the field, there's a feeling now that
the time is here for moving the technology to test in
humans," said Dr. Richard A. Andersen, professor of
neuroscience at the California Institute of Technology, who
is working on his own device for the brain. Still, for the
trial, there is trepidation mixed with anticipation.
"A disaster at this early stage could set the whole field
back," said Dr. Dawn M. Taylor, a research associate at
Case Western Reserve University and the Cleveland Veterans
Affairs Medical Center, who is testing similar systems in
monkeys.
Devices have long been implanted in the brains of patients
with Parkinson's disease to deliver pulses of electricity
that reduce tremors and rigidity.
But systems like BrainGate do not deliver current.
Instead, they listen to the electrical signals produced by
the brain's neurons as they work. The aim is to discern a
pattern of neuronal activity indicating the intention to
initiate a particular physical movement.
In typical monkey trials of neural implants, the animals,
which are not paralyzed, are trained to perform a task,
like moving a cursor with a joystick, while a tiny subset
of their neurons is monitored.
After different patterns of neuronal signals are matched
with different body movements, cursor control is shifted to
their brains.
In some studies, the monkeys eventually appeared to realize
that they no longer had to move their arms to perform the
tasks.
In a sense, this is a form of mind reading, scientists say.
But in addition to passively letting its thoughts be read,
the brain also learns to control the cursor actively, just
as it acquires any new skill.
The quadriplegics in the trial will not be able to move
their arms to train the system, making things a little
harder. Instead, they must imagine moving their arms.
Researchers have already shown that this can be done. Dr.
Philip Kennedy, a neurologist in Atlanta who started Neural
Signals Inc., implanted electrodes into several severely
disabled people starting in 1996, and at least one could
type through this method, though only three words a minute.
Some other implants have been tested briefly on people
undergoing brain surgery for other reasons. Dr. Jonathan R.
Wolpaw of the New York State Department of Health has
developed a system that does not require implants but uses
electroencephalography to pick up brain waves using sensors
attached to the scalp.
Though Cyberkinetics is not the first to try neural control
in people, it seems the most intent on bringing a product
to market, perhaps by 2007 or 2008, said its chief
executive, Timothy R. Surgenor.
Started in 2001 and based in Foxborough, Mass., the company
has raised $9 million for the project.
Cyberkinetics argues that its system will perform better
than other systems tested on people so far. Devices that
use sensors outside the skull do not pick up signals as
clearly as electrodes under the skull. And though Dr.
Kennedy implanted two electrodes per patient, the
Cyberkinetics chip has 100 electrodes. That means more
neurons can be monitored, providing clearer information,
the company says.
To implant the chip, a small hole will be cut in the
patient's skull, above the ear. The chip, which measures
about 2 millimeters (or just under one-tenth of an inch)
square, will be placed on the surface of the brain at the
motor cortex, which controls movement.
The electrodes, which are like spikes protruding from the
chip's surface, will extend into the brain to a depth of 1
millimeter.
The surgery will be performed at Rhode Island Hospital by
Dr. Gerhard Friehs, an associate professor of neuroscience
at Brown and a co-founder of Cyberkinetics, who performed
the operations on the monkeys. Another neurosurgeon without
connection to the company will monitor the procedure to
ensure that financial interests do not dictate proceeding
with surgery if it is not safe.
Technicians from Cyberkinetics will later visit the
participants, whose identities will not be disclosed at
first, several times a week at their homes to test the
system for an hour or two a day. The trial will last about
a year, and then the chips will be removed in a second
operation.
Some scientists question whether the benefits will outweigh
the risks.
One reason is that the signals from the chip are carried
out of the body by wires coming through the skull. When the
system is to be used, a cable will be connected to the
wires.
The cable will carry the signals to a cart full of
electronic equipment that will analyze them and convey the
results to the computer. The opening in the skin is
permanent and poses a risk of infection.
"We don't like to hang around with wires coming out of our
head," Dr. Kennedy said. His system used brain implants
that transmitted signals by radio, so no break in the skin
was required.
Some experts also question Cyberkinetics's requirement that
participants in the trial be able to talk. Such people, the
experts say, can control computers through other options,
like speech recognition systems or head or eye movements.
"If you are only talking about moving a cursor up and down
on the screen, you don't need to get into the brain to do
that," said Dr. Miguel Nicolelis, professor of neurobiology
at Duke.
In contrast, Dr. Nicolelis said, the system he is
developing will control a robot arm, making
three-dimensional movements that will be too complex to do
without a neural implant. Dr. Kennedy performed his
experiments on people who could not talk and had virtually
no other means of communicating.
Mr. Surgenor of Cyberkinetics, however, said that having
participants who could talk would speed development of the
system.
"We need the feedback of what they are imagining when it
doesn't work and what they are imagining when it works," he
said.
Dr. Jon Mukand of the Sargent Rehabilitation Center in
Warwick, R.I., who will be the principal investigator of
the trial and will select the participants, said the system
had been proved safe in tests on 18 monkeys.
Infections were rare and treatable, Dr. Mukand said, and
the incidence should be even lower in people, who
understand the risk.
Dr. Donoghue of Cyberkinetics said the prototypes for many
medical devices, including pacemakers and cochlear
implants, had involved wires coming out of the body.
One uncertainty is whether the implants will move around
over time or cause scarring. Either could lead to loss of
the neuron signal.
Another question is whether the system, if it does work,
will prove superior to more mundane methods like voice
recognition or even Dr. Wolpaw's electroencephalography
system.
Cyberkinetics said it expected that its system would be
faster than other methods, perhaps allowing people to type
20 to 30 words a minute, as fast as a healthy person could
type on a BlackBerry hand-held computer.
Marcie Roth, executive director of the National Spinal Cord
Injury Association, said the needs of paralyzed people
varied. A system like BrainGate "could be fantastically
useful for some people," she said.
Cyberkinetics said that it did not intend to sell the
current version of BrainGate, but that it hoped eventually
to offer an improved model. It would use miniaturized
electronics and would be fully implanted in the brain,
transmitting information without wires. The price is likely
to be in the tens of thousands of dollars, the company
said.
Eventually, the system may come in a form that does not
have to be calibrated by technicians each time it is turned
on. It would always be ready to use, as if it were a part
of the body.
"You don't wake up and turn on your hand," Mr. Surgenor
said.
http://www.nytimes.com/2004/04/13/health/13BRAI.html?ex=1082849470&ei=1&en=c
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