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From The Sunday Times
February 10, 2008
Blind taught to ‘see’ like a bat
BLIND British children are to be taught a pioneering bat-style echolocation
technique to visualise their surroundings.
The children are learning how to build up detailed images of the world around
them by clicking their tongue and interpreting the sound as it echoes back.
The technique is used by animals such as bats, dolphins and whales to navigate
and hunt in the dark.
Bats are able to manoeuvre around caves and catch tiny insects on the wing by
emitting short bursts of high-pitched noise and reading the sound waves as
they bounce back to their highly evolved ears.
There is emerging evidence that blind people can harness their sense of
hearing – which is often more acute – to interpret reflected sound and
create detailed mental images of their surroundings, including the distance,
size and density of objects.
The technique is being piloted in Glasgow, where 10 children aged five to 17
are being taught by staff from Visibility, one of the city’s oldest
charities for the blind. The children are learning how to make the clicking
sound and how to use the technique even in noisy urban areas, including the
underground system.
Blind people in America, where human echolocation was pioneered, have learnt
to differentiate between people, trees, buildings and parked cars by
interpreting the pitch and timbre of the echo they produce. Practitioners
say they can determine the height, density and shape of objects up to 100ft
away.
People using echolocation can determine the distance they are from an object
by the length of time it takes for the sound to travel back. Its position
can be established by whether the echo hits the left or right ear first. The
size of an object can be determined by the intensity of the echo. A smaller
object reflects less of the sound wave. The object’s direction of movement
can be established by the pitch of the echo, which is lower if it is moving
away from the source.
Echolocation has been endorsed by Professor Gordon Dutton, one of Britain’s
leading paediatric ophthalmologists, who wants the technique to be taught to
blind and visually impaired people across the country. There are about
385,000 registered 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 echolocation being used – it’s quite stunning. It has
been demonstrated to me that it absolutely works.
“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.”
The project in Glasgow follows a visit last year by Dan Kish, a 41-year-old
blind man from California, who pioneered the technique. Kish, who runs the
not-for-profit organisation World Access for the Blind, has also been
commissioned by the charity Common Sense to present his method to the
families of blind people in Poole, Dorset.
His command of the technique is such that he can ride a bicycle on public
roads and distinguish between different types of fruit on trees merely by
clicking his tongue. A video on the website YouTube shows Kish and a number
of his friends demonstrating their skills.
Ben Underwood, a teenager who lost his sight when he was three, has also
become a celebrity in America because of his ability to use echolocation to
ride a bike and to go skateboarding.
Although there have been no scientific studies of echolocation, supporters say
it can hugely improve the lives of blind and partially sighted children.
While using a cane allows blind people to identify obstacles in their path,
echolocation is said to provide 360-degree “vision” and can give them far
greater freedom.
“It’s a type of seeing in its own right, which probably uses similar brain
imaging mechanisms to eyesight,” Kish said.
“Students almost invariably become more confident, move faster and participate
in more activities,” he continued. “They show improved posture and regard
themselves as more able to direct themselves through their environment with
less need for others.
“They are freer, and better able to choose the quality of life they wish to
achieve, rather than have this chosen for them.”
Fiona Sandford, chief executive of Visibility, added: “This is a pioneering
technique that will transform the lives of young blind children.
“We have trained four visually impaired adults and they are now using their
skills to train children. We hope to roll this out to adults. I have seen it
being used and it works.”
Belgium’s federal police use a unit of blind officers specifically for their
acute sense of hearing, in analysing phone taps and bugged conversations in
investigations of terrorism, drug trafficking and organised crime.
The detectives can separate the voices of different speakers and pick up sonic
clues such as whether a suspect is in a railway station or a restaurant or
whether the caller is using a land-line or mobile phone. Some officers have
even identified the make of car suspects are using.
A detective in Antwerp, Sacha van Loo, 36, who is trained in echolocation,
correctly identified a drug smuggler as Albanian from his accent when
sighted colleagues thought the man was Moroccan.
Hollywood has also depicted the heightened senses of the blind. In the 2003
film Dare-devil, Ben Affleck plays a New York lawyer, blinded in childhood,
who transforms himself into a masked crime-busting superhero by night, using
his acute hearing as a “radar sense” to “see” through the dark.