Blind and visually impaired people have the potential to
use echolocation — a technique similar to that used by bats and
dolphins — to determine the location of an object, according to new
research.
Researchers from the University of
Southampton examined how hearing, and particularly the hearing of
echoes, could help blind people with spatial awareness and navigation.
The
study also examined the possible effects of hearing impairment and how
to optimise echolocation ability in order to help improve the
independence and quality of life of people with visual impairments.
Researchers
conducted a series of experiments with sighted and blind human
listeners, using a ‘virtual auditory space’ technique, to investigate
the effects of the distance and orientation of a reflective object on
ability to identify the right—versus—left position of the object.
They
used sounds with different bandwidths and durations (from 10—400
milliseconds) as well as various audio manipulations to investigate
which aspects of the sounds were important.
“We
wanted to determine unambiguously whether blind people, and perhaps even
sighted people, can use echoes from an object to determine roughly
where the object is located.
“We also wanted to
figure out what factors facilitate and restrict people’s abilities to
use echoes for this purpose in order to know how to enhance ability in
the real world,” Dr Daniel Rowan, lead author of the study, said.
The
results showed that both sighted and blind people with good hearing,
even if completely inexperienced with echolocation, showed the potential
to use echoes to tell where objects are.
Researchers
also found that hearing high—frequency sounds (above 2 kHz) is required
for good performance, and so common forms of hearing impairment will
probably cause major problems.
“Some people are
better at this than others, and being blind doesn’t automatically confer
good echolocation ability, though we don’t yet know why. Nevertheless,
ability probably gets even better with extensive experience and
feedback.
“We also found that our ability to use
echoes to locate an object gets rapidly worse with increasing distance
from the object, especially when the object is not directly facing us.
While
our experiments purposely removed any influence of head movement, doing
so might help extend ability to farther distances,” Rowan added.
The
knowledge gained from this study will help researchers to develop
training programmes and assistive devices for blind people and sighted
people in low—vision situations.
The study was published in the journal Hearing Research.
Source : Business Line Via PTI , 21st May 2013
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