To begin to understand hearing loss, it is first necessary to have a basic understanding of how we hear. There are two pathways by which sound waves produce the sensation of hearing:
Air Conduction - Sound waves collected by the outer ear move down the ear canal and hit the eardrum causing it to vibrate. The three bones in the midlle ear (malleus, incus and stapes) are moved and the incus pumps in and out of the fluid in the inner ear or cochlea. This results in a fluid wave that corresponds to the sound wave originally collected by the outer ear. The cochlea contains thousands of hair cells which are moved by the wave and when they are stimulated sufficiently a nerve impulse is created. This is transported to the brain via the auditory nerve where it is interpreted as sound.
Bone Conduction - This occurs when a sound wave or other source of vibration cuses the bones of the skull to vibrate. These vibrations are transmitted to the fluid in the cochlea and a wave is created which results in hearing.
There are two basic types of hearing loss; conductive and sensorineural.
These involve physical issues that prevent sound moving through the outer and middle ear.
These are from damage to the hair cells in the inner ear or the nerves responsible for carrying nerve impulses to the brain.
Hearing loss may be gradual or sudden. It may be mild resulting in minor difficulties in conversation or as severe as complete deafness. The severity and speed at which hearing loss occurs may give us clues to the cause.
If you cannot determine the cause of your hearing loss, then you should see a doctor. If you feel that it is probably due to age but aren't sure then you could see a private audiologist. Other symptoms that require a trip to the doctor include the following: