An older client reports to a nurse. "My daughter says there is something wrong with my hearing. I am not so sure. Yes, I have some problems hearing, but I am 78 years old. What does she expect? I noticed that at Christmas dinner, with all the racket around, I had some trouble. I think it is that my granddaughters mumble a lot, just like all young people. I guess it has been getting steadily worse; it seems to be both ears as well." Based on the client's description, the nurse suspects which of the following?