Researchers
try out the new device which, when strapped to the side of the head,
sends a beam of light through the skull to track brain activity. The
gadget detects simple yes/no answers for paralytic patients, helping
them communicate better with the help of a computer
Peggy Chun is a popular artist known for bold watercolour paintings
that capture the spirit of her home in Hawaii. But in 2002, the painter
was diagnosed with Amyotrophic Lateral Sclerosis (ALS), also known as
Lou Gehrig’s disease. This neurologic disorder progressively destroys a
person’s motor neurons: Chun can feel, see, smell, taste, think and
imagine, but can no longer move in any way. She is, in medical
parlance, “locked-in”.
But now, a team of US scientists has
developed a device - to be strapped to the head - that can help Chun
communicate again, albeit in simple yes-and-no answers.
ALS is
the most frequent cause of locked-in syndrome, which begins with
numbness in the extremities and progresses upward until all motor
function disappears.
“Usually the last thing you lose is eye
movement,” says University of Virginia cognitive psychologist Dennis
Proffitt. “When you lose that, you are cognitively alert, you can
think, you can feel, but you can’t move a thing. As a result, you can’t
communicate in any way. It’s awful.”
Proffitt, whose research
focuses on creating computer interfaces that help improve human
cognitive processes, is working with colleagues at Georgia Tech and a
company called Archinoetics to develop the technology that may make
life for locked-in patients more bearable.
The device involves
an interface that uses functional Near InfraRed imaging (fNIR) to
assess activity in Broca’s area – a part of the brain where verbal
working memory occurs.
Just above the left ear, researchers
strap a device that projects a light beam through the skull and
measures changes in blood volume and oxygenation when Broca’s area is
engaged.
Then, the researchers ask subjects to count in their
head when they want to activate the verbal working memory and initiate
a “yes” response. When they want to say “no”, subjects think of clouds
or rest or think “la la la”. It’s an easy process and does not require
a lot of training.
“It
was hard for us to think of something we could ask a person to do –
something easy to control, something you can turn on and off – that we
could measure in this way,” explains Proffitt. “What we came up with
was subvocal speech … talking to yourself.”
But he quickly stresses: “It’s not reading your thoughts. We can’t do that.”
Scientists
know the kinds of things the brain is doing because different parts of
the brain are activated when a person performs different functions.
Proffitt’s system simply detects whether or not a particular area of
the brain is actively engaged at the time.
“You could be
counting, or you could be reciting a poem. We couldn’t tell the
difference,” Proffitt says. “We just know the kind of thing you’re
doing.”
The system is still primitive, Proffitt admits, but it’s a start.
“Right
now, it’s an on/off switch. What we want to do is to get continuous
control so the person is not just activating (verbal working memory)
but can say by how much. So, not just ‘yes’ or ‘no’, but small to
large…,” he says. “If we could achieve that in the next few years, it
would be a huge improvement in what we will be able to do with the
technology.”
But Peggy Chun isn’t waiting for the technology to evolve. She’s using the
system now as a tool for creativity.
With
the sensor in place over her left ear, the artist activates Broca’s
area to select shades from a palette that show up on a computer screen
as horizontal gradations of colour. She calls her new oeuvre “brain
art”.
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