Forget any reference to a disability. Art shows should just mix-in the art from those with disabilities along-side the rest of the art. At the end of the day, what does it matter that the artist has a disability? It is the Art we are judging. It's the only way to put their work on a "fair" footing with the rest of the artwork. The disabled artists I know don't want their work purchased out of pity; they want it purchased because it is GOOD.
Also, at least in the eyes of some, including myself, having exhibitions of "special categories" of artists unintentionally promotes a concept that the participants are "second class" artists at best. One who can't play with the "big boys". Such events are usually created out of good-heartedness, but make no mistake, the stigma is there.
Don't hold "special" events for artists with disabilities.....just hold Art events, and make sure their work is hung alongside the work of others.