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By Steve Nomer

Since I was a boy, I've heard comments about blind people having developed a more acute sense of hearing in compensation for their loss of vision. As I grew older, however, I began to learn that this concept of blind people being superior hearers was not accepted by some experts in matters of the blind.

I found a recent study on this subject rather interesting. It indicates that a person who has been blind since birth or

lost vision at a very early age might, indeed, have some extra abilities when it comes to hearing sounds. Apparently, though, not every blind person will develop these additional abilities. The study found that those with plastic brains will have a better chance of having superior hearing abilities.

While at first glance it might seem that a plastic brain isn't something one would be excited about having, in this case "plastic" refers to the ability of the brain to change its way of doing things. Specifically, if a person is born blind or becomes blind very early in life, his or her brain may change the function of its visual processing center, or visual cortex, into a center for processing of auditory input, thus devoting many more resources and energy than another person's brain to analyzing sounds. This comes as a result of one who is blind using hearing to navigate and gather information about his or her environment which is deprived him or her due to lack of vision.

In the study, both blind and sighted people were given the task of listening to sounds and determining their exact locations. It was found that, using just one ear, none of the sighted people could place the sounds. Five of the twelve blind people, however, could place the sounds’ origins extremely accurately. Then, using positron emission tomography, better known as PET scans, it was found that the five who could place the sounds successfully had greatly increased brain activity in the visual cortex of the brain. Thus, it appears that their brains, not needing all the processing power normally reserved for handling visual input in a sighted person, had switched to using the visual cortex to analyze sounds.

A few other studies have indicated similar increased activity in the visual cortex of the brains of blind people when they were reading Braille. The activity was said to be similar to that of a sighted person reading print. It appears that our brains can function in more than just the ways in which it normally does, if circumstances demand.

So it does, indeed, appear that, at least in some blind persons, other senses may adapt to compensate for lack of sight. Perhaps, then, having a plastic brain is a good thing!

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