The tongue is an incredible organ that gives humans access to taste through the thousands of taste buds that cover it. These taste buds are collections of nerve-like cells that send messages to the brain. It is one of the most sensitive organs in the body greater than the sensitivity to touch of fingertips.
However, it is also notoriously difficult to study because of its position inside the mouth. A new study from Mike Richardson, a research associate in psychology at the University of Berlin, introduces the tongue as an organ that can potentially help blind or visually impaired people.
FDA-Approved Device That Helps the Blind See Through Their Tongue
Richardson specializes in a field known as sensory substitution, which is a field of science that combines psychology, neuroscience, computer science, and engineering. Scientists have created sensory substitution devices (SSDs) in the past that convert sensory information from one type of sense to another.
One example of SSDs is the BrainPort which was first developed in 1998. The device converts the video captured in a camera into moving patterns of electrical stimulation on the tongue's surface. Using a small lollipop-like device called a tongue display that consists of 400 tiny electrodes, it draws a picture of what is in the camera's video feed into the tongue.
BrainPort can help stroke victims maintain their sense of balance and visually impaired people as it feels like someone is drawing images on the tongue using a lollipop.
The device received approval from the US Food and Drug Administration (FDA) in 2015 for the company Wicab to market the device that helps the blind "see."
How Does the Tongue Help Blind People See? Researchers Investigate One of the Most Sensitive Organs in the Body
Focusing Attention on the Tongue
The device has been around for many years, but the world has not caught up with it. Richardson used the Posner Cueing paradigm, named after American psychologist Mike Posner, to measure visual attention when using the device.
He defined attention in an article in The Conversation as a set of processes that brings from the environment to conscious awareness. According to Posner, attention could be cued by visual stimulus. For example, seeing something moving out of the corner of the eye easily catches one's attention to that area, perhaps due to evolution to help humans protect themselves from predators.
But this also happens between senses, known as "cross-modal" attention, when things that appear in one sense can also influence other senses. Richardson and his colleagues built a variation of the Posner Cueing paradigm to see whether the tactile attention on the tongue's surface is the same as the tactile sensory in the hands that let blind people see.
They found that the tongue responds to cue information like hands or vision, but attentional processes are limited as they can easily over-stimulate and cause sensory overload. It's the sensory processes on the tongue that are affected by sound, so if it is paired with an auditory interface to guide attention and reduce sensory overload.
In terms of real-world use, the device helps translate visual information but can also be overstimulating. Therefore more tweaks are needed to make it a reliable instrument to help blind or deaf people navigate.
RELATED ARTICLE: A Speech-to-Touch Sensory Substitution Device Improves Hearing in Hearing-Impaired without Training
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