We just had a long discussion about this that wound up in the trash can for being off topic.
In short, yes, her ear problem will effect her voice, but I actually think the quality of her voice more likely changed due to other factors. She had been dealing with the problem with her ear since 2000 actually. But the type of problems that she has with her voice now I don't think can all be traced to an ear problem. (such as being out of breath and cutting off notes short)
Also an ear problem is not necessarily the death nell of your voice. Brian Wilson, the lead singer of the beach boys for example was also permanently deaf in one ear, yet always sang on pitch.