The blind who 'see' with sound

  • Science & Technology
  • Monday, 31 Aug 2015

Hirosawa (right) pausing to snap a photo as he learns the art of echolocation. Despite being blind, the Japanese man is an avid photographer. Photos: TNS

The space before the blind man was a riddle he needed to solve. Was he facing a house, a car, a hedge, a fence, a tree, or open space?

Ryo Hirosawa pushed the tip of his tongue hard to his palate and made a sharp click.

He tried to focus on the form and timing of the click’s echo as it came back to his ears, as fast as a blink.

But he couldn’t quite decipher the shape of the sound. Was is scattered, as if it hit foliage or chain link? Was it a clean pulse ricocheting off a stucco wall? Was it hitting multiple objects and coming back in fragments, milliseconds apart?

“Are there solid objects in here or are there sparse objects in here?” asks his instructor, Brian Bushway.

Hirosawa kept clicking, and edges in the acoustic landscape gradually began to emerge as a faint picture.

“There is a tree, I think, here, which is tall, and I see a house behind,” Hirosawa says.

They step into the yard to find out whether he was right. Bushway taps his cane against the tree trunk and reaches up to grab a branch and shake the leaves. “Sparse objects,” he says. “Feel it, know what it sounds like.”

He knocks the wood panel of a wall.

“A house,” Bushway says. “Awesome, very good.”

Hirosawa (right) listening to the echo of his clicking tongue as Bushway teaches him how to use echolocation.
Hirosawa (right) listening to the echo of his clicking tongue as Bushway teaches him how to use echolocation.

This quiet cul-de-sac of old bungalows in Long Beach, California, is at the centre of an unorthodox movement to teach blind people to navigate using tongue clicks for orientation.

Daniel Kish, 49, lives and runs World Access for the Blind there. Bushway is one of his two main instructors.

Their students learn to better perceive the space before them, sending out sonar, like dolphins or bats, to get an acoustic read on their surroundings – a human form of echolocation.

Kish has worked with scientists to study how the brain accomplishes this. A brain imaging study on Kish and Bushway by researchers at the University of Western Ontario found that when they were echolocating they were processing acoustic information in the spatial-visual part of the brain, not the part normally associated with hearing.

Kish had retinal cancer when he was born and lost both eyes soon after his first birthday. He unconsciously began making clicking noises with his tongue to navigate, as other blind children often do. But unlike many other parents, who worried that their child might be ostracised for sounding weird, his mother and father didn’t discourage him from clicking, and let him roam the neighbourhood like any other 1970s kid.

He rode bikes, climbed trees, and delivered his mother’s Avon catalogues to neighbours near and far. He didn’t understand how the clicking was helping him until he was 11, when a friend pointed out that he was doing what he had read bats do.

“I hadn’t thought about it,” he says. “I was just a squirrelly kid who liked to be active.”

Kish (right) teaches blind people from around the world, including Bushway, how to use echolocation to navigate.
Kish (right) teaches blind people from around the world, including Bushway, how to use echolocation to navigate.

Bushway lost his eyesight in the eighth grade from optic nerve atrophy. But walking through school in Mission Viejo, he could still see columns in the hallway, even count them. He was baffled. He closed his eyes and they were still there.

When he met Kish in 1996 at the Braille Institute in Anaheim, California, he told him about this phenomenon. Kish concluded that his brain was forming a spatial image from the ambient sound reflecting off and sluicing through the columns.

“I was imaging acoustically,” Bushway, 32, says. “The brain creates images whether you send it patterns of light or patterns of sound.”

Kish, by then a mobility and orientation instructor, started working with him to process those sounds, but also taught him to use the click when the ambient sound didn’t offer enough information.

Bushway, who had loved to play ice hockey and mountain bike, was inspired to see Kish breaking through the barriers that he was terrified would cage him in.

“Wow, this guy lives his life independently,” Bushway recalls thinking. “He does all these fun activities. He could ride a bike. He likes walking and exploring neighbourhoods and playing laser tag.”

Kish showed Bushway how to skateboard, using a long cane to read the road surface and curbs, and the clicking to spot parked cars, intersections and turns ahead.

With the help of another instructor, Andy Griffin, who could see, they started mountain-biking trails and fire roads in California’s Santa Ana Mountains.

Griffin would lead, with zip ties around his spokes to send out a blizzard of clicks. Kish and Bushway would follow making their own clicks to locate larger objects such as trees and boulders.

In this sonic caravan, they could charge over roots, ruts and rocks as speedily as most mountain bikers – with perhaps a few more scrapes to show.

In 2001, Kish established World Access for the Blind to teach the clicking technique. Since then, his team has travelled to more than 34 countries. Kish’s other instructor, Juan Ruiz, won a Guinness World Record for the “Fastest 10 obstacle slalom on bicycle – blindfolded.” He rode 20m with the obstacles placed at random in 25.43 seconds.

They began getting news coverage around the world.

Kish’s high profile has drawn some criticism in the world of blind advocacy. The main complaint is that the clicking would seem off-putting to the public, leading to further stigmatization. Another was that all the hoopla reinforced a misconception that blind people have mysterious powers.

The National Federation of the Blind is neutral on Kish’s work. “All blind people use echolocation to an extent,” says Chris Danielson, a spokesman for the federation. “Mr Kish has a unique way of doing it that seems to work for him and others.”

He says many blind people tap their canes for a similar effect in certain circumstances.

Kish says the click is more effective because it is directional, and doesn’t change with the surface of the ground or the angle of the cane.

Brandon Shin, 17, came to Kish for help two years ago after slowly losing his sight. His father was extremely suspicious. But Shin says he “harangued” his parents so much, they let him have lessons.

Now he clicks all the time, and recently hiked Runyon Canyon by himself. “Just the cane and my clicking,” he says proudly.

He says some kids at school made fun of him. But others have been fascinated with it.

His father, Mike Shin, says his own scepticism has faded as he’s watched his son manoeuvre around obstacles as though he could see them.

“Sonar has given Brandon self-esteem and courage,” he says. “From a parent’s point of view, we’re worried he’ll get hurt. But we’re proud. He’s doing it better than we expected.”

In Long Beach, Hirosawa is still struggling to catch the fast-fleeting echo. If he stands 1.5m from a wall, the echo followed his click in less than a hundredth of a second.

Bushway knows it’s difficult.

“So the hierarchy is, visual information is the loudest, then tactile information, then acoustic information,” he says.

Hirosawa came to Long Beach from the small village of Fukuoka, Japan, for training. It’s his second trip here.

At home, he says, his parents lock him in the house because they are so concerned for his safety. He says blind people in his country aren’t autonomous. He sneaked out when he could, but the main path into town follows a river, and he fell in several times.

He and Bushway walk and cross a busy street and turn back, aiming their clicks to the corner. The echo is sharp, almost metallic.

“There is a house,” Hirosawa says. “The surface is really smooth.”

Bushway tells him to take note of the unique echo from that house, so when he walks back he will know to turn down that lane to reach Kish’s bungalow. “That’s a great acoustic landmark there.”

Hirosawa keeps clicking, taking in the distinctiveness of the sound.

The next time he sneaks out of his parents’ house, he will listen for similar spots. And he’ll have sonic bread crumbs to lead him back home. – Los Angeles Times/Tribune News Service

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