Blind Soldier Sees With His Tongue

During much of the 20th century, neuroscientific consensus held that after childhood brain structure could not be changed in the lower brain and the neocortices. The prevailing view was that strengthening or weakening neural connections allowed change in these structures, but the structures were immutable. Then along came Paul Bach-Y-Rita and neuroplasticity.

Bach-Y-Rita developed the approach of sensory substitution.

A woman came to him desperate for help. Her brain's vestibular system damaged, she often felt she was falling even when lying flat on her bed. Walking, she hugged walls, strode spraddle-legged. Like a soldier in battle, she and her body lived on high alert. The relentless stress was overwhelming her and undermining her health.

To treat her, Bach-Y-Rita used a computer attached to small electrodes on her tongue. He chose the tongue because of its high density of sensory receptors. In short, because it is extremely sensitive. As she learned to use this device, her vertigo gradually disappeared. She was able to stay balanced.

Her brain structure was not hard-wired. She, among others, showed that the brain is highly plastic in its ability to take over functions once performed by a different--but now damaged or missing--function.

BrainPort was Bach-Y-Rita's invention. Now it is being used for blind individuals.

Case in point. British soldier Lance-Corporal Craig Lundberg lost his eyesight in a rocket-launched grenade attack while serving in Iraq in 2007. He was told he would never "see" again. But now he can--with his tongue.

Lundberg uses a BrainPort device. For him, it involves a video camera resting on a pair of sunglasses in turn linked to an electrode on his tongue.

The camera converts image-pixels into electrical pulses which are sent to the tongue, where they cause a tingling sensation. Varying tingle strength is interpreted by him so he can mentally visualize and navigate his surroundings. For example, white pixels are strong, while grey are medium, and black have no signal.

Such adaptation is possible because blindness or deafness generally only means one kind of loss--loss of ability to transmit sensory signals to the functional brain area. The pathways remain. The transmitter--retina for eyes or cochlea for ears--does not.

Lundberg says that using the tongue electrode is like "licking a nine volt battery." Learning to see with it takes intensive training.

It helps him see shapes and even read letters.

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