I find this interesting, as I've had the condition for 30 years+ (working in industrial environments, flying rotary/fixed, racing motocross, rock concerts, etc.). It's only noticeable when the ambient noise level is way down, but completely imperceptible in a cockpit. In the medical examiner's quiet area, I can still hear his hearing test. Unfortunately, it doesn't seem to mask the wife's voice.
How did this lead to the loss of a medical? In other words, how does it prevent you from performing flight crew duties?