Putting Motion Where Your Mouth Is

It lets us converse with others, sing along to the radio and play a flute. Without it, we couldn’t taste that chocolate cake and lick our lips. But since when can a tongue open a door, operate a wheelchair or type?

That’s exactly what Maysam Ghovanloo, Ph.D., has in mind, with something he calls the Tongue Drive system. The new assistive technology dreamed up by this electrical engineer and assistant professor at the Georgia Institute of Technology (Georgia Tech) in Atlanta promises to transform the lives of people with severe disabilities, even those with high-level spinal cord injuries.

With the Tongue Drive, a magnet the size of a grain of rice is attached to the tip of the tongue with tissue adhesive, or by implantation or piercing. The person also wears something like a phone headset, mounted with two extensions along both cheeks, or an orthodontic brace inside the mouth. Here, an array of magnetic field sensors detects specific tongue movements for an unlimited number of different commands, each tailored for the person’s abilities, oral anatomy and personal preferences.

As the tongue (without much thought or effort) quickly and oh-so-accurately turns and stretches, curls and pokes, the sensor’s signals are immediately transmitted, wirelessly, to a laptop computer that is programmed to perform a variety of functions — everything from moving a computer cursor to changing TV channels. The research team has also begun to develop software to connect the system to communication tools such as text generators, speech synthesizers and readers. The user can also switch the system to standby mode so he or she can eat, talk or sleep, for instance, without wasting battery power.

Ghovanloo and his graduate research assistant Xueliang Huo are working on eventually chucking the bulky laptop by connecting the Tongue Drive system to a smartphone (a mobile phone with PC-computer capabilities) or PDA (personal digital assistant) attached to the person’s clothing or wheelchair. “Theoretically, it’s also possible to assign a letter of the alphabet or certain command to each tooth, so just by touching your tongue to your teeth, you can type or do other things,” says Ghovanloo, who began the project three years ago.

A motor output, the tongue is similar to the fingers and hands. But unlike these parts of the body, which are connected directly to the brain through the spinal cord, the tongue enjoys a direct route to the brain through a cranial nerve. “So even if someone is paralyzed all the way up to the neck, they can still use their tongue,” says Ghovanloo, who notes it generally escapes damage in severe spinal cord injuries or neuromuscular diseases. “It’s a huge advantage for an assistive technology to rely on tongue movement because there’s a broad spectrum of individuals with different disabilities that can benefit from it.”

If that little magnet on the tip of the tongue empowers a disabled person to answer the phone and surf the Internet, “someone who was isolated can now connect with the rest of the world. They can get an education and pursue an occupation,” he continues. And if the Tongue Drive can wheel them around the house and turn lights on and off, “they become a lot more independent, relieving a dedicated caregiver of continuous care.”

So far, with funding from the National Science Foundation and the Christopher and Dana Reeve Foundation, Ghovanloo’s invention has been tested twice, both times on six able-bodied student volunteers who tried out its ability to operate a power wheelchair. The research went off without a hitch. Soon, those with severe disabilities will get their turn, in trials conducted in collaboration with the Shepherd Center, an Atlanta-based catastrophic care hospital.

“I’m really fascinated by doing research at the border of electrical engineering and medicine,” says Ghovanloo. “As long as I can remember, I’ve always liked to help people. I feel that this is the best area I can do that in.” And if the Tongue Drive can make it out of the lab and into the world, “that would be the ultimate satisfaction for me.”