For people who are blind, hearing the bulk of a big building or the open space of a covered entranceway isn’t far-fetched or imaginary. For them, it’s a bit like seeing through their ears.
Whether they know it or not, people who are blind receive valuable cues about their environment from the echoes that bounce off objects – echoes they catch in their ears and that are transmitted to their brains. Now, this approach to finding one’s way – called echolocation or flash sonar – is gaining momentum as a systematic, helpful way to navigate without sight.
The technique is called flashSonar because it uses sound waves that make flashes in the brain. By clicking with the tongue, a person can send a signal out to the environment. That signal bounces off objects – perhaps walls, buildings or cars – and sends back auditory images of the environment. People also can hear these echoes when they walk, stomp their feet or tap their canes. In a Jan. 23 NPR segment called “A Blind Woman Gains New Freedom, Click by Click by Click,” Julee-Anne Bell said the clicking tongue is in the same position as when it licks peanut butter from the roof of one’s mouth.
The use of this system in more rudimentary ways has come to be called echolocation. But Daniel Kish, a totally blind certified orientation and mobility instructor, coined the term FlashSonar because it involves more serious visioning than detecting doorways or overhead objects. FlashSonar can help blind travelers with scene analysis, identification and recognition of complex environmental features, perception of small objects and fine details, and high speed movement (running or biking speeds). For more information, please read Daniel Kisch’s article, Flash Sonar: Understanding and Applying Sonar Imaging to Mobility. This can be found at: https://nfb.org/images/nfb/publications/frfr301/fr300107.htm
Daniel Kish is a world-renowned teacher of this method, and has been called a blind Batman. He is cofounder and president of World Access for the Blind, a California-based organization that focuses on developing innovative approaches to improving the functioning of blind people. He holds master’s degrees in psychology and special education.
Kish is blunt in his instructions to parents who want their children to learn successful mobility techniques.
“They have to get their hands off their kids, for one,” he said in an interview with BCF. “Most of these blind kids are being dragged around by someone or they’re being directed by someone or the environment’s being carefully modified around them, by someone.”
This idea of leading the blind has become more prevalent because of a greater emphasis on the idea that professionals, not children and their families, are most important when it comes to dictating children’s development and education, Kish said. He believes children should have the experience of learning by themselves, moving by themselves, to figure out what is around them. A child who is given a white cane in toddlerhood will grab it, bang it against things and want to learn what those things might be. What does it sound like, for example, when the cane whacks against a wrought-iron fence, a brick wall or a wooden plank?
Parents encourage their seeing children to explore by using “educational attention,” Kish said. A parent might say of a sunrise or a tree, “look at that. Isn’t it pretty?” But this kind of communication is almost totally absent between blind children and their parents, and most blind children do not want to move because they don’t see what’s out there. They might crawl backward, for example, because they don’t want to hit objects with their heads, Kish said.
“So we get facilitated movement,” which means someone is leading the movement, Kish said.
This sense of freedom and exploration must be cultivated by drawing attention to everyday soundscapes. Kish suggests singing into containers of different sizes and listening to the sounds, or walking through the neighborhood and listening for bells, traffic or sound bouncing off objects. Count parked cars by bouncing sounds off them during the walk. Allow the child to describe sounds: are they softer, harder, bigger or smaller?
Next come instructional exercises, again using sounds encountered in daily life. Help the child learn to “scan” by moving his/her head, much the way a seeing person might do by moving the eyes. Clicking the tongue while doing this kind of scan can tell the child, for example, where the play structure on the playground is located.
Kish said there are two major uses for echolocation: to follow an object such as a wall or to target an object the person wants to locate. This might mean walking in the direction of an object the person hears and adjusting the tongue clicks to deal with outside noise such as traffic or rain. To teach a child to walk straight, he/she might start by walking very close to a long wall and hearing its echo, then moving gradually farther away.
World Access for the Blind has a number of articles about flash sonar, and has a training program for parents and their blind children.
Flash Sonar has inspired brain research to determine how it works. Researchers measured the functional brain activity of an echolocation expert with early blindness (Kish) and another with late blindness. They studied sounds that contained clicks and their returning echoes versus control sounds that did not contain the echoes but were otherwise acoustically match. The study showed activity in the visual cortex of both men studied, but did not detect changes in the auditory cortex.
The research shows “uncanny resemblance” to the visual process that takes place in the brain. This might mean that the brain recruits parts of its visual cortex to accomplish this process.
Disclaimer: Please note that the lists shown below are not recommendations of BCF nor is this list all-inclusive but is representative of websites that offer information. The Blind Children’s Fund always recommends that you use information only from knowledgeable and well-recognized sources since there are many scam-types of programs now proliferating the Internet.
Read about this brain research in the following paper:
Brain Scan Studies and Perspectives in Neural Science: Neural Correlates of Natural Human Echolocation in Early and Late Blind Echolocation Experts, World Access for the Blind, www.waftb.org, PLoS ONE (Public Library of Science), May, 2011. By Thaler L, Arnott SR, Goodale MA, University, Western Ontario.
Read more about flash sonar from four articles, recommended by Kish:
- Seeing Through Sound, Vital Signs, June 18, 2014. By Sanjay Gupta. http://edition.cnn.com/video/?/video/international/2014/06/18/spc-vital-signs-brian-bushway-blindness.cnn&video_referrer=#/video/international/2014/06/18/spc-vital-signs-brian-bushway-blindness.cnn
- Getting Around by Sound: Human Echolocation, Neuroanthropology: Diverse Perspectives on Science and Medicine, June, 2011. By Prof. Greg Downey | Macquarie University, Sydney. http://blogs.pios.org/neuroantropology/2011/06/14/getting-around-by-sound-human-echolocation/
- FlashSonar: Understanding and Applying Sonar Imaging to Mobility, Future Reflections, National Federation of the Blind, March, 2011. By Daniel Kish. https://nfb.org/images/nfb/publications/fr/fr30/1/fr300107.htm