Hearing loss refers to reduced hearing that results from a problem in one or more parts of the ear, and can affect people of all ages. Sound waves usually move through the external ear canal and vibrate the eardrum. The vibration of the eardrum is then passed on through the middle ear bones onto the cochlea (the hearing organ). The sensory cells of the cochlea are then stimulated and transmit signals to the auditory nerves (hearing nerves) and to the brain. The brain recognises these transmitted signals as sounds.
There are three types of hearing loss:
- Conductive hearing loss - occurs when sound waves are not transmitted properly from the outside environment to the cochlea
- Presbycusis - is the hearing loss that occurs with ageing
- Sensorineural hearing loss - occurs when the cochlea or auditory nerves are damaged