Wednesday, June 14, 2023

You Can Taste Scenes- Tongue Display Unit (TDU)


Picture A shows the Tongue Display Unit (TDU)

The tongue display unit is a version of a tactile aid device that helps visually impaired individuals in conveying visual material by using the tongue. Tactile aid devices developed after the invention of the video camera, and the original development was made in the 1960s. It included a video camera that converted its images through an array of 400 small electrodes that were placed on the back of a user. The posts would vibrate depending on what was being shown on the screen, they would have a specific pattern of vibration for specific images. The subject would then guess what was being shown through the camera based off the vibrations on their back. To begin, the subjects were not able to decipher what the vibrations meant, they were just vibrations. With as little as a few hours, the subjects were able to analyze the patterns and create a mental image of what is being "shown" to them. It is not only able to work when the electrodes are on the subjects back, it is able to be moved around the exterior of their body and it would have no effect on their analyzation of the image. this goes to show that the brain portrays the skin as a sense organ that can distinguish patterns of touch.

Picture B shows the original version of visual tactical aid device created by Neuroscientist Dr. Paul Bach-y-Rita

Now, the tongue display unit is the newest of the tactile aid devices and it doesn't go on the external part of the body, it goes internal, on the tongue. The tongue is a very sufficient part of the body for a touch array because its receptors are not only close to the skins surface, but the saliva from the tongue gives electrical conduction. The touch brain is susceptible to tongue stimulation, making the tongue a better than most of the external skin.  The array uses small, low voltage electrical transducers unlike the original invention that used intense vibrations. In recent studies when blind subjects use the TDU continuously it activates their visual brain regions.

Picture C shows the electrode array
When using the TDU, the array is placed on your tongue and the transducers send the low-voltage electrical current to your tongue in the pattern of the image's being shown on the screen. It is similar to its predecessors in the event of using vibrations/electrical currents to give the subject a visual of what is being seen on the screen. Within a few minutes to hours, subjects are able to recognize what is being shown for example shapes and numbers. With practice subjects should be able to move through a cluttered room, avoiding obstacles. Because the TDU is low energy, it means there are less components that are bulky making it easily portable.  They may even be able to stop a ball from rolling off a table, it is truly miraculous how this type of tactical aid can give better quality of life.

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