| dc.description.abstract | (Laymen) Abstract:
Echolocation is the ability to locate the objects and creatures around you by means of interpreting the reflected echoes, of sounds that bounce off of them. Human echolocation is a technique useable by any human, but most notably by the blind and visually impaired. The technique is similar to echolocation used by bats and dolphins, which use it to navigate in total darkness and under water.
There are two different forms of echolocation: active and passive. Actively producing sounds in order to receive localization information from the reflected echoes, is known as active echolocation. Passive echolocation is the interpretation of reflected echoes from sounds produced by your surroundings. Most blind and visually impaired already use some of the aspects of passive echolocation unconsciously. Active echolocation however, needs to be taught, just like the use of a cane. A trained echolocator can use echolocation to navigate his surroundings far beyond the reach of his cane and identify objects and people as if sighted.
The use of this technique requires sensitivity and rapid analysis of the properties of both self- generated sounds and its echoes, as well as the sounds and echoes produced by the surroundings. The possibilities and impossibilities, together with the known teaching methods of human echolocation are described and reviewed in detail, to better understand the influence recent research might have on teaching the technique.
FMRI analysis shows that trained echolocators, when presented with pre-recorded self-generated sounds and their echoes, have increased activation in brain areas associated with visual processing, most notably in the primary visual cortex (or calcarine cortex), as if they create a mental image. The accuracy, detection limits and abilities to identify objects with human echolocation have also been investigated and studies on these subjects will be reviewed here as well. Research in echolocating animals is also of considerable value in understanding the possibilities of the technique and the neural pathways involved. These and other recent research findings influence the way blind and visually impaired people are taught to use human echolocation and combine the technique with other tools. | |
