What kind of measures should one take when running a game which includes a [dis]abled player (or players) such as a blind of deaf player? Are there any technologies or styles which are particularly fitting or useful under these circumstances? Are there any technologies or styles which are particularly ill-fitting or not useful under these circumstances?

(I don't mean to be rude in grouping all disabilities together, and recognize that the answer varies based on the disability. Nonetheless, I am curious to hear some general answers.)