A new assistive technology developed by engineers at the Georgia Institute of Technology (Georgia Tech; Atlanta) could help people with severe disabilities lead more independent lives.

Not only does the Tongue Drive system allow individuals with disabilities to operate a computer, control a powered wheelchair and interact with their environments simply by moving their tongues, it's only moderately invasive compared to neuromodulation devices that require surgery to implant stimulation and interface systems into the brain.

Users only need to be able to move their tongues to operate the device. A small magnet, the size of a grain of rice, is attached to the tongue by implantation, piercing or, as a temporary fix, with tissue adhesive.

"The primary group of users who could benefit from this system are individuals with high-level spinal cord injuries because they still have full control over tongue motion," Maysam Ghovanloo, an assistant professor in the Georgia Tech School of Electrical and Computer Engineering, told Medical Device Daily. Ghovanloo invented the system with graduate student Xueliang Huo.

"These people can talk, eat and some can breathe on their own, while others use ventilators; as long as they can move their tongues repetitively, they can use this," he said. "The tongue has a direct connection to the brain through one of 12 cranial nerves, as opposed to hands and feet that need to connect to the brain through the spinal cord. Tongue or facial muscles aren't affected with high-level spinal cord injuries."

The small implanted magnet attached to the tongue is detected by an array of magnetic field sensors mounted on a headset outside the mouth or on an orthodontic brace inside the mouth. The sensor output signals are wirelessly transmitted to a portable computer, which can be carried on the user's clothing or wheelchair.

The sensor output signals are processed to determine the relative motion of the magnet with respect to the array of sensors in real time. This information is then used to control the movements of a cursor on the computer screen or to substitute for the joystick function in a powered wheelchair.

"Eventually, rather than a computer, it will be a PDA or smart phone that users carry on a belt or wheelchair," Ghovanloo said.

The system can potentially capture a large number of tongue movements, each of which can represent a different user command. A unique set of specific tongue movements can be tailored for each individual based on the user's abilities, oral anatomy, personal preferences and lifestyle.

Ghovanloo and his team have conducted three sets of Institutional Review Board-approved human trials with able-bodied student volunteers.

"It takes 15 minutes to explain the system to a user," he said. "Then it took them 10 minutes to familiarize themselves with using the system and another few minutes to define tongue commands [which included six basic commands as part of original experiments]."

As part of the training, users must repeat a movement 10 times for the computer to recognize and correlate specific signals to commands.

Now that Ghovanloo has confirmed that the basic technology works, he's talking with various companies, as well as a business incubator at Georgia Tech that spins off start-ups, about commercializing the device, which he expects would be priced at $5,000 to $10,000.

For now, he's seeking IRB approval to work with handicapped patients in cooperation with Shepherd Center and the Department of Rehabilitation at Emory University (both Atlanta).

Ghovanloo's team has also begun to develop software to connect the Tongue Drive system to other communication tools such as text generators, speech synthesizers and readers.

Current research was funded by the National Science Foundation and the Christopher and Dana Reeve Foundation.

One company that has developed a neurotechnology to assist disabled patients is Cyberkinetics (Foxborough, Massachusetts). Its BrainGate Neural Interface system is designed to improve the independence, mobility and communication of patients with advanced amyotrophic lateral sclerosis or other motor impairments (MDD, Oct. 17, 2006).

BrainGate is currently being tested in a pilot clinical trial being conducted under an investigational device exemption from the FDA.