Hearing loss is part of the normal ageing process. It begins as early as your 40s but usually happens very gradually, affecting both ears.
Approximately 42% of individuals over the age of 50 and 71% over age 70 have some degree of hearing impairment. However, only one third of people in the UK who could benefit from hearing aids wear them.
How does the ear work?
The ear is divided into 3 parts:
Outer ear: the visible external part or “pinna” and the ear canal. The outer ear funnels sounds towards the ear drum or “tympanic membrane”, causing it to vibrate.
Middle ear: an air-filled cavity behind the ear drum, containing a chain of 3 small bones called the ossicles which pass sound vibrations along to the inner ear.
Inner ear: the cochlea, an organ shaped a bit like a snail-shell, filled with fluid and special hair cells. Sound vibrations stimulate the hair cells which send messages along the hearing or auditory nerve to the brain where they are interpreted as sounds. Another part of the inner ear is the vestibular apparatus. Movement of fluid inside this part sends messages to the brain about changes in position of the head, and so is important in balance.
Types of hearing loss
There are 2 main types of hearing loss, although it is possible to have both.
Conductive hearing loss; failure of conduction of sound waves to the cochlea. There are many causes including ear wax, diseases of the ear drum or ossicles or fluid in the middle ear cavity (“glue ear”). Sometimes the hearing loss is temporary.
Sensorineural or “nerve” deafness due to faulty signalling from the cochlea. This latter type is what happens in age-related hearing loss, although there are other causes too such as genetic factors, noise-induced deafness and certain drugs. Age-related hearing loss is caused by wear and tear of the hair cells and is permanent but hearing aids can be a huge help.
Do I need to see a doctor?
Gradual hearing loss is not usually of concern but some symptoms can suggest an underlying medical problem.
Sudden hearing loss occurring over less than 72 hours , in one or both ears, should prompt an urgent medical opinion.
Other signs for which you should seek medical advice include:
- rapidly increasing hearing loss
- persistent hearing loss or tinnitus in ONE ear only (see section on tinnitus)
- hearing loss associated with other symptoms such as vertigo (dizziness or a spinning sensation), ear pain or discharge, altered sensations in the face or drooping of the face.