Wednesday, May 13, 2009

Tongue sees what eyes can't

Tongue sees what eyes can't.

By Gabriella Boston | Wednesday, May 13, 2009.

Seeing with the tongue? Yes, it's possible. A recently developed device helps
blind people read books and street signs as well as play sports and games by
stimulating nerves on the tongue.

"I played tick-tack-toe with my daughter," says Erik Weihenmayer, who lost
his vision at age 13 because of a congenital eye disease. "And I caught her
cheating," adds the 40-year-old mountain-climber, author and inspirational
speaker with a chuckle.

He's doing this by using a product called BrainPort. Essentially, a camera
mounted on the blind person's head sends visual information via wires to a
processor. The processor translates that information into gentle electrical
stimulation patterns through a flat device that's worn on the tongue.

"People describe it as a picture being drawn with bubbles," says Robert Beckman,
chief executive officer of Wicab Inc., the company that makes BrainPort. It has
not yet been cleared by the Food and Drug Administration.

Those bubbles provide signals that are sent to the brain's visual cortex for
interpretation. The idea of letting one of our senses make up for the deficiency
of another is called "sensory substitution," says Mr. Beckman, who is testifying
before Congress today about a different version of BrainPort that aims to help
people with balance deficiencies caused by conditions such as stroke.

In other words, if the eyes don't function well, let different nerves - in this
case, those of the tongue - do the work by sending enough information for the
brain to make an informed interpretation.

"It works because you don't actually see with your eyes. You see with your
brain," Mr. Weihenmayer says.

Adds Mike Oberdorfer, a program director at the National Eye Institute, a branch
of the National Institutes of Health: "It's the plasticity of the brain that
makes it possible. ... In this case, it's inputting a perception, except the
perception is not a visual; it's based on touch. But in the end, it creates the
same perception [in the brain]."

In the case of BrainPort, a blind person can see size, shape, location and
motion of objects in black and white. Anything with a sharp contrast - black
letters on a white background - is easier to see, Mr. Weihenmayer says, than
images of low contrast - say, people dressed in pastels set against foliage in
a park.

However, the picture - even in a high-contrast context - is much cruder than
that of a sighted person's perfect vision.

"It has to do with the limitations of the hardware," Mr. Beckman says.

The main limitation is the tongue device. It features 400 tactors - electrode
points - which can be compared to pixels. The more tactors the tongue device
has, the clearer the picture.

"We're still in the early stages of this technology," Mr. Beckman says, adding
that he hopes to add tactors - maybe up to 20,000 - to future devices to gain
additional clarity.

Another challenge to using the device is that it requires training: You have to
learn the settings of the apparatus (like any manual camera, it has to be
adjusted for distance and aperture) and you have to train the brain to make the
correct interpretations and connections. It's like learning a new language.

"Think about how long it takes a child to learn how to read," says Mr.
Weihenmayer, who has used the device for about 20 hours.

Speaking of children, Mr. Weihenmayer says if the device lands in the hands of
blind children - which it hasn't yet - there is no telling what the potential
can be because of the superplastic nature of young brains.

For adults, however, Mr. Beckman predicts that the BrainPort will be added to
other tools already in a blind person's toolbox, including a cane or a guide dog.

Mr. Weihenmayer agrees: "I don't see it as the end-all device. But it will be
another tool to integrate [blind people] into the world."

Social isolation is a common condition for blind people.

"This device helps make you feel safer and more confident," he says.

The cost - when it becomes available on the market - is estimated to be about
$10,000; by comparison, seeing guide dogs cost up to $17,000 to train but
usually are offered to blind people free of cost.

Mr. Weihenmayer's hope is that FDA approval will happen quickly and the product
will become mainstream for blind people nationwide so they can experience the
wonder and usefulness of the device.

"Reading was one of the coolest things I've ever experienced," says Mr.
Weihenmayer, who also has used the device to rock climb, which he normally does
without any type of visual aid. "And the leaping flame of a candle. It's amazing."

He should know about cool and amazing experiences. Mr. Weihenmayer was the first
blind man to reach the summit of Mount Everest. (Erik Weihenmayer) (National Eye Institute) (BrainPort)

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Mrs. Kathy
Visual Impairments Resource/Consult
Greenville Elementary

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