Hello colleagues:
I thought I ought to forward the following item.
Regards,
Robert
----- Original Message -----
From: "Ike Presley" <presley@afb.net>
To: "AERNET" <aernet@lists.aerbvi.org>
Sent: Monday, July 13, 2009 8:10 AM
Subject: [AERNet] FW: [vipnews] Scientists Develop Echolocation In Humans
ToAid The Blind
This looks like interesting research.
-----Original Message-----
From: vipnews@googlegroups.com [mailto:vipnews@googlegroups.com] On Behalf
Of editor@vipnews.org.uk
Sent: Friday, July 10, 2009 9:19 PM
To: vipnews@googlegroups.com
Subject: [vipnews] Scientists Develop Echolocation In Humans To Aid The
Blind
Science Daily
Scientists Develop Echolocation In Humans To Aid The Blind
ScienceDaily (June 30, 2009) - A team of researchers from the University of
Alcalá de Henares (UAH) has shown scientifically that human beings can
develop echolocation, the system of acoustic signals used by dolphins and
bats to explore their surroundings. Producing certain kinds of tongue clicks
helps people to identify objects around them without needing to see them,
something which would be especially useful for the blind.
"In certain circumstances, we humans could rival bats in our echolocation or
biosonar capacity", Juan Antonio Martínez, lead author of the study and a
researcher at the Superior Polytechnic School of the UAH, tells SINC. The
team led by this scientist has started a series of tests, the first of their
kind in the world, to make use of human beings' under-exploited echolocation
skills.
In the first study, published in the journal Acta Acustica united with
Acustica, the team analyses the physical properties of various sounds, and
proposes the most effective of these for use in echolocation. "The almost
ideal sound is the 'palate click, a click made by placing the tip of the
tongue on the palate, just behind the teeth, and moving it quickly
backwards, although it is often done downwards, which is wrong", Martínez
explains.
The researcher says that palate clicks "are very similar to the sounds made
by dolphins, although on a different scale, as these animals have
specially-adapted organs and can produce 200 clicks per second, while we can
only produce three or four". By using echolocation, "which is
three-dimensional, and makes it possible to 'see' through materials that are
opaque to visible radiation" it is possible to measure the distance of an
object based on the time that elapses between the emission of a sound wave
and an echo being received of this wave as it is reflected from the object.
In order to learn how to emit, receive and interpret sounds, the scientists
are developing a method that uses a series of protocols. This first step is
for the individual to know how to make and identify his or her own sounds
(they are different for each person), and later to know how to use them to
distinguish between objects according to their geometrical properties "as is
done by ships'
sonar".
Some blind people had previously taught themselves how to use echolocation
"by trial and error". The best-known cases of these are the Americans Daniel
Kish, the only blind person to have been awarded a certificate to act as a
guide for other blind people, and Ben Underwood, who was considered to be
the world's best "echolocator" until he died at the start of 2009.
However, no special physical skills are required in order to develop this
skill. "Two hours per day for a couple of weeks are enough to distinguish
whether you have an object in front of you, and within another two weeks you
can tell the difference between trees and a pavement", Martínez tells SINC.
The scientist recommends trying with the typical "sh" sound used to make
someone be quiet. Moving a pen in front of the mouth can be noticed
straightaway. This is a similar phenomenon to that when travelling in a car
with the windows down, which makes it possible to "hear" gaps in the verge
of the road.
The next level is to learn how to master the "palate clicks". To make sure
echoes from the tongue clicks are properly interpreted, the researchers are
working with a laser pointer, which shows the part of an object at which the
sound should be aimed.
A new way of seeing the world
Martínez has told SINC that his team is now working to help deaf and blind
people to use this method in the future, because echoes are not only
perceived by their ear, but also through vibrations in the tongue and bones.
"For these kinds of people in particular, and for all of us in general, this
would be a new way of perceiving the world".
Another of the team's research areas involves establishing the biological
limits of human echolocation ability, "and the first results indicate that
detailed resolution using this method could even rival that of sight
itself". In fact, the researchers started out by being able to tell if there
was someone standing in front of them, but now can detect certain internal
structures, such as bones, and even "certain objects inside a bag".
The scientists recognise that they are still at the very early stages, but
the possibilities that would be opened up with the development of
echolocation in humans are enormous. This technique will be very practical
not only for the blind, but also for professionals such as firemen (enabling
them to find exit points through smoke), and rescue teams, or simply people
lost in fog.
A better understanding of the mental mechanisms used in echolocation could
also help to design new medical imaging technologies or scanners, which make
use of the great penetration capacity of clicks. Martínez stresses that
these sounds "are so penetrating that, even in environments as noisy as the
metro, one can sense discontinuities in the platform or tunnels".
Journal reference:
Rojas et al. Physical Analysis of Several Organic Signals for Human
Echolocation: Oral Vacuum Pulses. Acta Acustica united with Acustica, 2009;
95 (2): 325 DOI: 10.3813/AAA.918155 Adapted from materials provided by
Plataforma SINC, via AlphaGalileo.
SOURCE
http://www.sciencedaily.com/releases/2009/06/090630075445.htm
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