The Technology Related Assistance to Individuals with Disabilities Act of 1988 described an assistive technology device as "any item, piece of equipment, or product system, whether acquired commercially off the shelf, modified, or customized, that is used to increase, maintain, or improve functional capabilities of individuals with disabilities."
Assistive technologies can be "high tech" and "low tech:" from canes and lever doorknobs to voice recognition software and augmentative communication devices (speech generating devices).
Chronic illness can result in physical disability. People who have a chronic illness may deal with symptoms such as pain or muscle degeneration. Some of these individuals may need assistance with mobility. Some mobility aids include:
Mobility varies with each person. Some people with a physical disability may be able to walk with the assistance of a cane or a 
prosthetic. Some people, like those who are quadriplegic, may control their mobility device with their mouth or their head. Examples of assistive technologies that help their users with limited mobility include:
