Deaf people 'can develop super-vision'
People deaf from birth may develop a form of "super-vision" to compensate for their lost hearing, research has shown.
By Rebecca Smith, Medical Editor
Published: 6:18AM BST 11 Oct 2010
Parts of the brain that normally locate sound sources learn to do the same job using vision instead Photo: PA
Scientists believe the brain adapts to the loss of hearing by rewiring itself to enhance sight. Parts of the brain that normally locate sound can learn to do the same job using vision instead. Researchers made the discovery by studying cats – the only animal besides humans that can be born congenitally deaf. People who are born deaf or blind often report their remaining senses being enhanced.
Some experts believe that losing one sense early in life at a time when nerve connections are still being made allows the brain to rewire itself to compensate. In deaf cats, scientists found brain regions that usually handle input from hearing become reorganised. The area of the brain that would normally pick up peripheral sound can be rewired to boost peripheral vision. As a result, deaf cats – and probably humans who are born deaf too – have an enhanced ability to observe moving objects.
Study leader Dr Stephen Lomber, from the Centre for Brain and Mind at the University of Western Ontario, Canada, said: "The brain is very efficient, and doesn't let unused space go to waste. "The brain wants to compensate for the lost sense with enhancements that are beneficial. For example, if you're deaf, you would benefit by seeing a car coming far off in your peripheral vision, because you can't hear that car approaching from the side; the same with being able to more accurately detect how fast something is moving." The findings are reported online today in the journal Nature Neuroscience.
Dr Lomber and his team are conducting the research to improve understanding of how the brain handles cochlear implants, devices that can help the profoundly deaf hear again. One question they want to answer is if the brain rewires itself to compensate for loss of hearing, what happens when hearing is restored? "The analogy I use is, if you weren't using your cottage and lent it to a friend, that friend gets comfortable, maybe rearranges the furniture, and settles in," said Dr Lomber. "They may not want to leave just because you've come back."
