Assistive technology plays very important role in the life of the people who are severely disabled due to quadriplegia, spinal cord injuries, central nervous system disorders or traumatic brain. Assistive technologies help them to lead a self supportive independent life. This paper provides the brief description about the various assistive technologies which has been developed until now for the severely disabled persons and its limitation. Further Tongue Drive System incorporating wireless assistive technology, which can overcome the limitation of previous related technologies, is discussed. Tongue Drive System is a tongue operated non-invasive or minimal invasive, unobtrusive and effective technology to control many devices in their environment. It helps users with the ability to drive power wheelchairs and access computers using their unconstrained tongue motion.