Individuals who are severely paralyzed as a result of spinal cord injuries, stroke, cerebral palsy, etc generally find it extremely difficult to carry out everyday tasks without continuous help. In this research, the PI will develop a new assistive technology to enable individuals who are severely paralyzed to convey their intentions to their environment by accessing a portable computer or personal digital assistant. The PI's approach is based on the observation that the tongue and mouth occupy an amount of sensory and motor cortex in the human brain rivaling that of the fingers and the hand. As a consequence, the tongue and mouth are inherently capable of sophisticated motor control and manipulation tasks with many degrees of freedom. The tongue is connected to the brain via the hypoglossal nerve, which generally escapes severe damage in spinal cord injuries. Tongue muscle is similar to heart muscle, in that it does not fatigue easily. Furthermore, the tongue is not influenced by the position of the rest of the body, which can be adjusted for maximum user comfort. These advantages, coupled with the accessibility of tongue movements without penetrating the skin, suggest that the tongue might be employed as an excellent intermediate connection to the brain to establish a noninvasive brain-computer interface. The PI will explore this possibility in the current project within the context of a new device called the Tongue Drive System (TDS). TDS consists of an array of magnetic sensors located either inside the mouth (e.g., attached to the outer surfaces of the teeth via an orthodontic brace) or outside of it near the user's cheeks (e.g., mounted on a headset similar to head-worn microphones). The sensor array measures the magnetic field of a small permanent magnetic tracer, the size of a grain of rice, which is attached to the tongue by means of tissue adhesives, implantation, piercing, or clipping. Sensor signals are transmitted wirelessly to the external PC/PDA, where the data are processed to determine in real time the coordinates, orientation, and relative motion of the magnet with respect to the array of sensors. This information is then used to control the movements of a cursor on the PC/PDA screen and to perform all other functions that an able-bodied individual can do with a mouse computer input device. The PC/PDA will have WiFi or Bluetooth connections to a number of other devices, including a desktop computer and powered wheelchair, in the user's environment.
Broader Impacts: This research will help the most severely disabled individuals, particularly quadriplegics, to lead more active, self-supportive, satisfying, and productive lives. Paralysis is considered to be one of the most expensive types of disabilities. Solutions such as the TDS will help reduce healthcare and assisted-living costs, increase the employability of people with disabilities, and allow users to participate more fully in society while relieving the burden on family members and caregivers.
