I cannot speak to partial deafness, but I used to work in an anechoic chamber. It is indeed soul-suckingly disturbing after short periods of time. Even a totally "silent" environment has tremendous amounts of reverb and low-level reflected noise: you just filter it out automatically. In an anechoic chamber, this noise is gone, and your filter goes haywire. It starts filtering things that aren't there. You start hearing your own blood vessels in your eardrum, yes, but you also perceive a kind of disturbing anti-noise. It's very hard to describe.
Top it off with the fact that usually such rooms are entirely sealed off and that you're standing or sitting on a big mesh trampoline floating in the center of the room, and it all comes to one seriously creepy experience after about ten minutes.