People with high-level spinal cord injuries typically lose control of their arms and legs meaning they can no longer get around without some sort of adaptive assistance device. Quadriplegics have long relied on a type of control system for electric wheelchairs called the sip-and-puff system.
This type of control system allowed the user to move forward and backwards in an electric wheelchair by sipping a straw or blowing into it. A group of researchers at the Georgia Institute of Technology (GIT) has devised a new method of controlling a power chair for those who no longer had functionality in their arms and legs. The new system uses the patient’s tongue to control the chair or to control the mouse cursor on a computer screen.
Maysam Ghovanloo, an assistant professor in the School of Electrical and Computer Engineering at GIT said, "This clinical trial has validated that the Tongue Drive system is intuitive and quite simple for individuals with high-level spinal cord injuries to use. Trial participants were able to easily remember and correctly issue tongue commands to play computer games and drive a powered wheelchair around an obstacle course with very little prior training."
The clinical trial was conducted at the Shepherd Center in Atlanta and involved the attachment of a small magnet, roughly the size of a grain of rice, to the tongue of the patient with a tissue adhesive. The magnet was used as a tracer to allow the magnetic field sensors to register its movements. The users of the system wore sensors that look like headphones on the head to track the magnet.
The researchers say that the nerve that controls the tongue in patients with high-level spinal injury is typically not affected in the injury. Software translates the movement of the magnet into motion for the chair via wireless connectivity with a computer attached to the chair.
The chair motion can be controlled in a constant setting that allows the chair user to move along an arc or in a control method for new users that only allows one motion at a time. According to the researchers, the Tongue Drive system can be used to create as many movement commands as the user can comfortably remember.