The most well known and perhaps oldest assistive device for the blind and visually impaired is the white cane. Fortunately though, a lot of innovative solutions have been added over the years. What about a special shoe that with the help of a camera warns of any obstacles on the sidewalk via sound and vibrations? The Austrian start-up Tec-Innovation is working on this together with the Graz University of Technology, as reported in last week’s best-read story.
There is still a world of difference between a shoe that gives warnings and actually being able to see obstacles. But a group of scientists from several universities is working on a solution: A brain implant. This implant should (partially) give blind people their sight back. Richard van Wezel, professor of visual neuroscience at the University of Twente and Radboud University (both in the Netherlands), is also involved in this research project.
It works as follows: A blind person has electrodes inserted into the visual cortex of their brain. The implant translates camera images into electrical shocks that stimulate brain cells in the visual cortex. This creates points of light that allow blind people to discern shapes. “Implanting electrodes in the brain. That sounds pretty heavy because the skull has to be opened up first. And it basically is. But ask a neurosurgeon about this and they will say it’s not such a big deal. The visual cortex is a large area so you can put a lot of electrodes in there. One hundred at the moment. Electrical activity creates points of light that enable an image to be formed. This replaces the eyes with a camera, so to speak.”
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Simplified image made up of points of light
It cannot be compared to ‘normal’ vision, but the image provides enough information to differentiate between different objects. “A highly simplified image, built up from points of light. A neural network filters the most relevant visual information in advance. This makes it possible to navigate your way around and see the difference between a sidewalk and a road,” Van Wezel explains.
The first test subject received the implant last year in Spain. The test will be extended if all goes well. Van Wezel: “They are working on this not only in Spain, but in other places as well. The research focuses mainly on people who once were able to see. Primarily because they are able to describe what they perceive. People who are blind from birth do have a visual cortex. But brain scans show that it has been taken over by other brain functions. More research is needed to find out if it also works for them.”
But Van Wezel is hopeful that it will succeed. “Look at the cochlear implant, which hundreds of people get in the Netherlands every year. This allows the deaf to understand speech with as few as 15 to 20 electrodes in their cochlea. That this works so well is really a miracle. The visual cortex is a large area and, in theory, you could place a lot more electrodes here, which in turn would allow for more detailed vision.”
Electrodes that last longer
For tje time being, the focus is on improving the AI system. “How fast should the camera translate images? What information is relevant? And what information is not? These are all things that you can train a neural network to deal with,” says Van Wezel. The scientists are also looking for electrodes that last longer. The current ones last about two years. “You put something in the brain that doesn’t really belong there, and connective tissue starts to grow around it. This causes signals to get through less and less well over time. We want technology that is – as it’s beautifully called – biocompatible. This is one of the biggest issues we’re working on right now.”
Whether blind people will ever see ‘normally’ with this prosthesis, Van Wezel dare not say. ” We can make a map of the sight from the visual cortex, so to speak. That can be translated reasonably one on one to a specific place in the brain. If you are talking about color perception, for example, then this is much more complicated. It is a utopian thought that they will ever see color; we still know far too little about that. It’s not yet clear exactly where this takes place in the brain.” Then, laughing, “You could ask yourself if that’s such a bad thing. We also watched black and white TV for years, right?”
Belt that helps recognize facial expressions
Van Wezel is working on several innovations for the blind and visually impaired. For instance, he came up with a special belt that helps recognize facial expressions. A camera translates facial expressions into vibrations for the belt via AI software. Each emotion is accompanied by a different vibration signal. “This can help blind and visually impaired people recognize emotions when they are talking to someone,” he begins. “The neural network is trained to recognize facial expressions, but you could train it in the same way for eye contact. Is the other person in the conversation paying attention to the visually impaired person?”
Personally, he is not familiar with the Austrian system featured in our best-read article. But it does have advantages over other types of aids, van Wezel points out. “Take the Orcam, a pair of glasses that helps the visually impaired and blind to read labels, among other things. The glasses sit on the ears and read out what it says. Like the Austrian system, it warns of objects, but not via vibrations but rather with audio. The disadvantage of this is that you are constantly being alerted in your ear throughout the day. While you actually want to keep your ears open for surrounding noise or traffic noise. The Austrian system does not interfere with hearing, which is a major advantage when navigating unfamiliar territory.”
Even though aids do not completely replace sight, Van Wezel believes it is important to continue developing different systems and aids. “It is relatively rare for people to be completely blind. There are different degrees of blindness and it differs per person how bad their vision is. Sometimes someone can navigate just fine on their own, but does need support in reading a label. It’s different for everyone.”
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