UW scientists use senses from tongue to aid disabled

With a few additions to the tongue, paralyzed people could feel the touch of a loved one and blind people could make out a spatial orientation of their surroundings.

Though it sounds like science fiction, the device to enable these actions is being developed and tested at UW-Madison by researchers Kurt Kaczmarek and Paul Bach-y-Rita.

The device they have developed, called the Tongue Display Unit, uses tiny electrodes to reroute impulses to the brain.

This is accomplished because the tongue is super-saturated with sensory neurons, bathed in electrically conductive saliva and, compared to a fingertip, needs only 3 percent of the voltage required for sensory stimulation. The device is made up of a tiny array of 144 copper electrodes plated with gold. Gold, though more expensive than copper, is present because of its non-reactive nature.

“When you normally pass an electrical current through copper in the mouth, it stains the tongue green,” explained researcher Kurt Kaczmarek.

Though subjects will not notice any visual alterations, they may notice varying sensations.

“It feels like a tingling vibration,” Kaczmarek said. “It’s a very subjective thing — some people have said it’s like soda bubbles, while others say it’s like an arm falling asleep. We are aware of no adverse side effects, and I am so confident of this that I let my own children (aged 5 and 6) play with the device. They call it ‘the tongue tickler.’”

The tongue tickler has many potential uses, and will have multidisciplinary effects.

“Applications under consideration include biofeedback to aid persons with vestibular (balance) disorders, vision substitution, directional-navigational information for Navy SEALS — we demonstrated proof of concept for this under a DARPA grant — urban search-and-rescue teams and extra senses in video gaming,” Kaczmarek said.

The device will run on batteries, but could have a more surreptitious method of control.

To avoid cables connected to cameras and computers from going into people’s mouths, the researchers plan on using short-range radio-frequency transmitters that wirelessly broadcast signals across the cheek.

This technology is not that far away. Prototype devices are available for laboratory research right now, and commercial applications are only one to two years away.

The price of the device, currently as a prototype, is approximately $5,000.

Kaczmarek and Bach-y-Rita are also working conceptually on devices about the size of a retainer that could help people who have lost their sense of balance.

These devices have tiny sensors that will interface directly with the brain. The scientists said the next stage of that research will be to help pilots with spatial disorientation, particularly in the dark.

“The device would give you valuable information to tell which way is up, which is important when you’re not headed up,” Bach-y-Rita said.

The scientists’ colleagues are enthusiastic about the new device.

“This work is based on totally solid science,” said Dr. Deric Bounds, chair of the UW department of zoology.

However, analysis and critique always arise.

“It will, at least at first, be limited in resolution by the small number of points,” said Dr. Robery Dempsey, UW professor of neurological surgery. “[The image created by the device] may at first be a picture with only 144 dots to define it.”

Chris Mason, Badger Herald 

Project Directors

Our team is led by three project directors, Kurt Kaczmarek, Mitchell Tyler and Yuri Danilov, who have a combined total of 65 years of experience in neuroscience, biomedical science, and engineering. 

Our Research

Founded in 1992, the Tactile Com­mu­nication & Neurorehabilitation Laboratory (TCNL) is located at the University of Wisconsin-Madison.

We are a research center that uses the experience of many different areas of science to study the theory and application of applied neuro­plasticity, the brain’s ability to re­or­ganize in response to new informa­tion, needs, and pathways.

Our research is aimed at developing solutions for sensory and motor disorder rehabilitation.