According to the National Institute of Standards and Technology (NIST):
"Assistive technology [aka, adaptive technology] (AT) can be defined 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 the functional capabilities of individuals with disabilities. (29 U.S.C. Sec 2202(2))."
These are some links recommended by Christine Besko-Maughan, who runs the Adaptive Technology (AT) classroom at Valley Road. They may be useful in planning AT for your library: