Change in hearing

A change in hearing, admittedly usually hearing loss.

Basically, it's either:

Conductive deafness is where there is an abnormality between the sound getting to the outer ear and the nerves to the brain.
Sensorineural deafness is where there is a problem with the nerves from the cochlea to the brain.

Wax - very common.
Otitis media - middle ear infection. Very common. Causes ear pain.
"Glue ear" - fluid in the middle ear. Usually due too an effusion from otitis media.
URTI - often the Eustachian tube gets blocked leading to difficulties in equalising the pressures either side of the ear drum.
Foreign body, trauma, perforated ear drum and head injury can all lead to problems in hearing

Oldness - aka as age-related hearing loss or presbyacusis. People get old and hair cells in the cochlea get damaged. Thus, their hearing becomes less good.
Infections - measles, mumps or meningitis

An endolymph. Probably. Not. Well, actually it's South Park's represntation of God.

Meniere's disease - fluid gets stuck in the ear, escaping from the endolymph system in the ear. No, I don't really know what an endolymph is either.
Medications - aminoglycosides (particularly gentamicin and tobramycin), chemo and radiotherapy can all cause deafness. Aspirin can cause tinnitus.
Aural tumours - rare. Acoustic neuroma and choleastoma.

The first thing to do is differentiate between the two types of hearing loss. The key to this is Weber's test and Rinne's test.

Test	Conductive	Sensorineural
Weber	Loudest in affected ear. Blockage masks ambient sounds	Loudest in unaffected ear. Conduction is fine therefore the affected ear is just not working as well
Rinne	Bone conduction > Air conduction. The air canal is screwed so sound conducts better down the bone on the affected ear.	Air conduction > bone conduction. No problems with conducting sound and bone isn't as good as the air

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