If your worried about your hearing Condensation, try going to your GP and having your ears drained and cleaned prior to your medical or alternatively you can get these things called "ear candles" from health food or natural medicine shops that work well for cleaning your ears out, it makes a small difference in your hearing which could be enough to get you over the line if you have some existing hearing loss.
Reaction speed also plays a part in the test - be prepared to hit the button the instant you even think you hear something.