Blind children taught to see the world like bats

Published on Sunday 10 February 2008 00:36

BLIND children from Scotland are to be taught a pioneering echo-location technique copied from bats in an effort to help them visualise their surroundings.

The youngsters will be able to build up a mental library of images of the world around them by clicking their tongue and interpreting the sound as it echoes back. The technique, which is used by bats, dolphins and whales to navigate and hunt in the dark, is being piloted in Glasgow, where 10 children aged five to 17 are being taught by staff from the charity Visibility.

There is growing evidence that blind people can use their advanced hearing to interpret reflected sound as the distance, size and density of objects around them.

Leading paediatric ophthalmologist Professor Gordon Dutton has backed the technique and wants it to be taught to the 385,000 blind and partially sighted people in Britain.

"It's very exciting," said Dutton, of the Royal Hospital for Sick Children in Glasgow. "I have seen echo-location being used – it's quite stunning.

"Of course there will be scepticism and doubt, but the benefits are without question. It will make a massive difference to the lives of blind and visually impaired people."

Echo-location was pioneered in the US, where people have been able to differentiate between people, trees, buildings and parked cars by the pitch and timbre of the echo they produce.

They have even been able to determine the height, density and shape of objects up to 100ft away.

Distance can be calculated by how long it takes for the echo to travel back, position by whether it hits the left or right ear first, and size by the intensity of the echo, as a smaller object reflects less of the sound wave.

The direction a moving object, such as a car, is travelling can be calculated by the pitch of the noise, which is lower if it is moving away from the person.

The project in Glasgow was launched following a year-long visit by Dan Kish, a 41-year-old man from California who pioneered the technique and uses it to ride a bike and even distinguish different types of fruit on trees.

Another practitioner of echo-location, teenager Ben Underwood, who lost his sight when he was three, has become a celebrity in America because of his ability to use it to ride a bike and go skateboarding.