There are many kinds of hearing loss, but most fall into three types of hearing loss:
Conductive Hearing Loss:
This type of hearing loss is a condition of the outer and/or middle ear. It occurs when sounds from the outside world cannot be transmitted normally through the ear canal and/or middle ear to the inner ear.
The most common causes of conductive hearing loss can be a build-up of wax in the ear canal, perforated eardrums, fluid in the middle ear (common in children), abnormal bone growth (Otosclerosis) or damaged or defective ossicles (middle ear bones).
Sensorineural Hearing Loss:
This type of hearing loss happens when the delicate nerves (hair cells) in the inner ear break down.
They become unable to convert sound vibrations into the electrical signals needed by the auditory nerve pathways, preventing these signals reaching the brain. Working in a noisy environment or industrial noise (noise induced) and aging (presbycusis) are the primary reasons for this type of loss.
Mixed Hearing Loss:
This kind of hearing loss is caused by a combination of problems in the middle and inner ear.