When you wake up, before you hear any loud noises (such as your alarm clock), your hear is very sensitive and with very little outside noise, you usually hear a high pitched noise within your head. Waking up with this sound is perfectly normal. Perhaps it's this that is being mistake for hearing damage?
Have a look at this from http://www.tinnitus.org The meaning of tinnitus sounds In 1953 Heller and Bergman performed an simple and classic experiment. They placed 80 tinnitus free individuals (university members in a sound proofed room for 5 minutes each, asking them to report on any sounds that might be heard. The subjects thought they might be undergoing a hearing test, but actually experienced 5 minutes of total silence. 93% reported hearing buzzing, pulsing, whistling sounds in the head or ears identical to those reported by tinnitus sufferers. This simple experiment shows almost anyone can detect background electrical activity present in every living nerve cell in the hearing pathways as a sound. Although some areas of the auditory system may be more active than others, every neurone will contribute to some extent to the final perception of tinnitus. These electrical signals are not evidence of damage, but compensatory activity that occurs all the time in the auditory system of each one of us. Compensation can occur as a response to changes in our sound environment (e.g. silence) to hearing loss which may be a natural part of ageing, or to exposure to sudden noise. Its good to think of the sounds produced by this compensatory activity as 'the music of the brain'. Of those who DO experience persistent tinnitus, population studies have shown that about 85% do not find it intrusive, disturbing or anxiety provoking (something tinnitus sufferers find very hard to believe!). The reason for this is not so much because the quality or loudness of the tinnitus is different; in fact we have found that tinnitus is of a very similar type of sound in those who are bothered by it and those who are not.
