Science

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AP Photo/ Gene J. Puskar
Retired Marine Corps Cpl. Mike Jernigan
of McLean, Va., using the BrainPort.

New Technology Brings “Vision” to the Blind Via the Tongue

August 18, 2009 05:00 PM
by Shannon Firth
The BrainPort uses sunglasses, a camera and an electronic “lollipop” to stimulate the tongue to send signals to the brain, creating a new mode of optical sensation.

Bypassing the Eyes to See

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Neuroscientists at Wicab, Inc., a Wisconsin-based biomedical firm cofounded by neuroscientist Paul Bach-y-Rita, recently unveiled the BrainPort, Scientific American reported.

The BrainPort consists of a digital camera affixed to a pair of sunglasses. The camera collects visual information and sends it to a handheld control unit “which converts the digital signal into electrical pulses—replacing the function of the retina,” Mandy Kendrick explains in Scientific American.

From the control unit, the signals are sent to the tongue through a “lollipop” component that rests on the tongue. The tongue’s nerves receive the electrical signals, “which feel a little like Pop Rocks or champagne bubbles to the user,” Kendrick writes. From there, scientists remain unclear on whether the visual information is sent to the brain’s visual cortex or to its somatosensory cortex, “where touch data from the tongue is interpreted,” according to Kendrick.

The University of Pittsburgh Medical Center's UPMC Eye Center is developing standards with which to compare the BrainPort to other vision technologies such as retinal implants. According to Scientific American, the new devices can be used by the blind as well those with glaucoma and macular degeneration.

"We can't just throw up an eye chart. We have to take a step back and describe the rudimentary precepts that these people are getting,” Optometrist Amy Nau told Kendrick.

Background: “How Brainport Works”

Julia Layton, a writer for HowStuffWorks, explains that the BrainPort was built on the principle of “sensory substitution” via “electrotactile stimulation.” Simply put, electric currents sent through the skin—or in this case, the tongue—convey information to the brain through pulses using alternate channels.

Key Player: Paul Bach-y-Rita

Neuroscientist Paul Bach-y-Rita first introduced the idea of neuroplasticity—“using one sense to replace another”—in the 1960s, when most of his colleagues followed “localisationism,” the theory that sensory processes were hardwired and unalterable, Norman Doidge wrote for the Telegraph.

In Germany, working alongside a team of scientists studying vision, he presented an image to a cat, and saw that the image triggered activity in the primary visual processing area. More importantly, however, stroking the cat’s paw and making a noise also stirred activity in the cat’s visual area, Doidge reported.

Bach-y-Rita also saw his father Pedro recover from a stroke, and viewed his recovery as proof of neuroplasticity. His brother George, a medical student at the time, helped their father relearn to walk, teaching him first to crawl. Pedro went on to regain his speech and learned to write again on a typewriter. He even resumed his job as a professor, and remarried, worked, traveled and hiked until he had a heart attack and died while climbing in the mountains of Colombia.

Bach-y-Rita recalled his father’s autopsy. Upon seeing layers of his father’s brain, he felt “revulsion” but then an epiphany: “[W]hat the slides showed was that my father had had a huge lesion from his stroke and that it had never healed, even though he recovered all those functions. .. I knew that meant that somehow his brain had totally reorganised itself with the work he did with George.”

Videos: Understanding vision and its impact

There are many misconceptions regarding how vision works. Simon Ings, author of “The Eye: A Natural History” explains, “The eye doesn’t simply drink in the world. It hunts for what we need to know. It jumps, pans, anticipates, our every move. Still we imagine that our eyes are mere windows.”

There are also misconceptions about blindness as a disability. Dr. Oliver Sacks chronicled the struggle of a blind man who saw for the first time after surgery in an interview with Charlie Rose. “All his feelings, and his motivations, his strategies were those of a blind man…suddenly he had a new sense forced on him, and given to him,” Sacks told Rose. The story was later adapted into a movie in 1999, "At First Sight," starring Val Kilmer and Mira Sorvino.

Reference: How the brain works

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