The Oxford Dictionary of New Words: A popular guide to words in ...

ways of saying 'disabled'.
Etymology: Formed by removing the prefix dis- from disabled.
History and Usage: The word abled arose in the US; it has been
used by the disabled to refer to the able-bodied since about the
beginning of the eighties, and is also now so used in the UK.
The euphemistic phrases differently abled, otherly abled, and
uniquely abled were coined in the mid eighties, again in the US,
as part of an attempt to find a more positive official term than
handicapped (the official term in the US) or disabled (the
preferred term in the UK during the eighties). Another similarly
euphemistic coinage intended to serve the same purpose was
challenged. Differently abled has enjoyed some success in the
US, but all of the forms with a preceding adverb have come in
for considerable criticism.
Disabled, handicapped, differently-abled, physically or
mentally challenged, women with disabilities--this is
more than a mere discourse in semantics and a matter of
personal preference.
Debra Connors in With the Power of Each Breath (1985),
p. 92
In a valiant effort to find a kinder term than
handicapped, the Democratic National Committee has
coined differently abled. The committee itself shows
signs of being differently abled in the use of English.
Los Angeles Times 9 Apr. 1985, section 5, p. 1
I was aware of how truly frustrating it must be to be
disabled, having to deal not only with your disability,
but with abled people's utter disregard for your needs.
San Francisco Chronicle 4 July 1990, Briefing section,
p. 7
ableism noun Also written ablism (People and Society)
Discrimination in favour of the able-bodied; the attitude or
assumption that it is only necessary to cater for able-bodied