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Can people use sound to help them to 'see' like bats?

A team of researchers at Durham University have been looking into how sound might help people who are blind or partially sighted to navigate their way around.

As part of the study both blind and sighted people were taught how to make special clicking sounds with their mouth to help them to sense objects around them.

The researchers found that over the course of the study, all of the people who took part improved their echolocation skills, and of those who were blind, 83% reported better independence, mobility and wellbeing.

Echolocation is the use of sound to help a person or animal to navigate its surroundings.

It works when an animal or person makes a sound, and listens to the returning echo sound as it bounces off nearby objects around them.

Animals like bats and dolphins use echolocation to help them to get around and avoid bumping into things, in environments where there is little to no light.

Dr Lore Thaler, one of the lead authors of the study said: "In our research we asked people to make clicks with their tongue and mouth. We did this because previous work had shown that echoes from mouth clicks provide a great deal of information, and because mouth clicks can be made without breathing (which is useful if you are walking up a steep hill!), and using mouth clicks also keeps your hands free (which is great if you already use a guide dog or long cane and maybe have a bag to carry). "

She also said you could use other sounds: "like whistling or finger snaps, or using clickers like for training dogs."

Over the course of a 10-week training programme, 12 blind people, and 14 sighted people were taught how to use echolocation, and took part in a number of tests to try it out.

"We asked people to use clicks to determine the size of objects in front of them, the orientation of objects, and we also asked them to do a computer task, where they had to wear headphones and use keys on the computer keyboard to navigate corridors based on the clicks and echoes. We also asked them to navigate outside the lab, i.e. to try out the clicks and echolocation in a 'regular' environment." explained Dr Thaler.

Those people who were partially, or fully sighted had to wear blindfolds during the tests.

"We found that everyone learned, which was great. What was also fantastic, was that all people who were blind reported that the training in click based echolocation had improved their mobility, and 83% also reported that it had improved their independence and wellbeing. And this was after only 10 weeks of training." said Dr Thaler.

Dr Thaler hopes that the results of the study would help to encourage more people to try echolocation.

"Our study is evidence that training in click-based echolocation can improve lives of people with vision impairments, and that age or level of vision are not strongly limiting factors. People sometimes worry about stigma, i.e. they worry that making clicks in public would be considered unusual or odd. But from the reports of people who took part in our study this was not an issue, so stigma is probably much less of an issue than people think."