What’s the difference between assistive and adaptive technologies?

So asks one of our readers…and here is the beginning of an answer!
Adaptive technologies refer to special versions of already existing technologies or tools, usually used by people with disabilities such as limitations to vision, hearing, and mobility. For example, in the early 1900s, FDR used a special car with hand controls because he was paralyzed from polio (an interesting vehicle-look it up!).
Assistive technology is a broader term encompassing any light-, mid-, or high-tech tool or device that helps people with disabilities perform a tasks with greater ease and/or independence.
Good definitions and discussions are on http://www.fctd.info/resources/glossary.php, http://www.rehabtool.com/at.html, http://www.washington.edu/accessit/articles?109, and http://www.disabilityinfo.gov/digov-public/public/DisplayPage.do?parentFolderId=185.
Anybody want to chime in?