Deaf-gain is defined as "a reframing of 'deaf' as a form of sensory and cognitive diversity that has the potential to contribute to the greater good of humanity." (DSDJ, p. 1) The term is coined by Aaron Williamson of U.K.
H-Dirksen L. Baumann and Joseph J. Murray, Editors. "Deaf Gain: Raising the Stakes for Human Diversity." 2014.
H-Dirksen L. Baumann and Joseph J. Murray. "Deaf Studies in the 21st Century "Deaf-gain" and the Future of Human Diversity". Pp 210-225. http://joseph-murray.com/wp-content/uploads/ Murray-and-Bauman-Deaf-Gain-Oxford-DEDST-2nd-ed-FINAL.pdf
H-Dirksen L. Baumann and Joseph J. Murray. "Reframing: From Hearing Loss to Deaf Gain." http://dsdj.gallaudet.edu/assets/section/section2/entry19/DSDJ_entry19.pdf
Also see Deafhood.
You may also be interested in synesthesia.