Evaluation of a Tongue Operated Assistive Technology for Individuals With Severe Paralysis

A new assistive neuro-technology (ANT), called the Tongue Drive System (TDS), enables individuals with severe disability access their environment with nothing but their tongue motion. The human tongue is inherently capable of sophisticated control and manipulation tasks with many degrees of freedom. It can move rapidly and accurately within the mouth such that the tip can touch every single tooth. The direct connection between the brain and the tongue generally allows it to escape damage even in severe spinal cord injuries (SCI). Unlike the brain, the tongue is accessible, and its location inside the mouth affords a degree of privacy. TDS consists of a magnetic tracer, the size of a lentil, attached to the tongue by gluing, implantation, or piercing. The tracer generates a magnetic field inside and around the mouth that is detected by an array of magnetic sensors mounted on a wireless headset. Tongue-movement-induced changes in the magnetic field are sent wirelessly to an ultra-mobile computer or smartphone, carried by the user, which processes and translates every tongue motion to a particular user-defined function. Once an individual with disability is "enabled" to access a computing device, he/she can nearly do everything that an able-bodied individual can do with that device. This includes communicating, education, training, entertainment, and controlling other devices such as powered wheelchairs (PWC), assistive robotic manipulators, and other home/office appliances on a local area network (LAN). Even the individual's own natural or prosthetic limbs can be manipulated to move by functional electrical stimulation (FES). This study was intended to evaluate the TDS by the ultimate intended users, individuals with severe disabilities, who are the best experts for indicating the benefits and possible shortcomings of any new ANT. Our goal is to assess the acceptability and usability of the TDS for various tasks that are important in daily life such as computer access, wheeled mobility, and environmental control. Three groups of subjects were recruited: Group-A: Able-bodied subjects who already have tongue piercing Group-B: Able-bodied subjects who wanted to receive tongue piercing as part of this trial Group-C: Subjects with high-level disability, who wanted to receive tongue piercing as part of this trial Each group of subjects participated in a battery of tasks that quantitatively measures their performance in accessing computers and driving wheelchairs using the TDS. We also devised acceptable procedures for receiving a magnetic tongue piercing (required in order to use the TDS), and assess its potential safety issues.