Soldiers May Get "Sight" on Tips of Their Tongues

Yancey Hall
for National Geographic News

May 1, 2006

Feeling your way through a new environment with your tongue might seem like a bad idea.

But a new technology allows people to do just that by turning the supple organ into an extrasensory transmitter.

Mounted on the tongue, the so-called sensory-substitution technology converts signals from a camera or a sensor worn by the user into electrical impulses.

These impulses—described as feeling like champagne bubbles—are then transmitted through nerves in the tongue directly to the brain.

Military researchers say sensory-substitution technology could enhance police and military operations where vision is obstructed.

The Florida Institute for Human and Machine Cognition in Pensacola is testing such a device for scuba divers.

They hope the technology could one day give underwater soldiers hands-free extrasensory abilities similar to those of snakes and fish (related photo: snake "tasting" its surroundings).

Keeping Balanced

Armed with electronic compasses and depth sensors, the scuba divers testing the device receive electric impressions of underwater objects on their tongues.

Michael Zinszer, a former U.S. Navy diver now with Florida State University's Underwater Crime Scene Investigation School in Tallahassee, is helping with the tests.

He says he was able to feel the outline of underwater images on his tongue and locate the corresponding objects very easily.

He says the device could help investigators signal other divers and navigate through murky water.

Already the technology is poised to enter the commercial market as a tool to help millions of people with sensory disorders.

Neuroscientist Paul Bach-y-Rita of the University of Wisconsin-Madison first conceived a device called BrainPort more than 30 years ago. He founded Wicab, Inc., in 1998 to market the technology to help patients with balance disorders.

Robert Beckman, Wicab's president and CEO, says constant moisture and the right chemical environment make the tongue ideal for conducting electricity.

What's more, the organ has three major nerves, he says, that can provide "high-speed data flow" directly to the brain.

Patients suffering from balance disorders, usually because of damage to the inner ear, can use the real-time signals to help them judge correct posture.

"Within the first day of using the device we can train [the patients] to maintain their balance by keeping the electro-tactile signal in the center of their tongue," Beckman said.

"Within approximately five to ten days of using the device on a daily basis, patients start to gain significant retention periods of normal balance or greatly improved balance."

BrainPort has already been approved for use in balance-disorder patients in Europe, and Beckman anticipates that the U.S. Food and Drug Administration will approve it sometime next year.

Sensory Substitution

Other organizations are also developing sensory substitution devices similar to BrainPort.

Researchers at Harvard Medical School's Jenks Vestibular Physiology Laboratory in Boston, Massachusetts, have developed a way to implant electrodes on organs in the inner ear that send stimuli directly to the brain.

The device has been used successfully in animals to correct balance disorders.

The lab's director, Dan Merfeld, is quick to point out the difference between his technology and Wicab's.

"Sensory-substitution devices [such as BrainPort] send information through a different sensory channel, like the tongue, and the person learns how to use that channel," Merfeld said.

Since inner ear organs directly control the body's vestibular, or balance, system, "our device is really a direct sensory replacement," he said.

At the U.S. Naval Aerospace Medical Research Laboratory in Pensacola, Florida, principle research engineer Braden McGrath has been working on ways to use sensory-substitution technology to help jet pilots deal with spatial disorders.

"When you are flying a high-performance aircraft, your sense of touch and your vestibular system give you a false impression, which leads to spatial disorientation with pilots," McGrath said.

(See a related photo: Surviving in space—Which way is up?)

These disorders are often the causes of helicopter and jet crashes for both military and commercial aircraft.

"We train pilots to rely solely on instrumentation," McGrath said.

"But when the workload gets too high, pilots revert back to their natural state, which is to use your vestibular system and your skin-muscle-joint [sensory system], which are typically wrong when flying."

To combat spatial disorientation, McGrath and his team have developed "tactile display systems" that provide pilots with accurate information about their surroundings.

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