71.1% of over 70 year-olds and 41.7% of over 50 year-olds have some form of hearing loss.
Most people who experience hearing loss as they get older do so due to a condition called presbyacusis, caused by wear and tear to the tiny hair cells in our inner ear.
There are two types of hearing problem - 'conductive', when sound is not able to pass through the outer or middle ear, and 'sensorineural', when the inner chamber of the ear (cochlea) or the auditory nerve that transmits the sound signals to the brain are affected.
The sensorineural kind of hearing loss becomes more common as we get older, usually due to a condition called presbyacusis.
Conductive hearing problems can include:
- middle ear infections
- collection of fluid in the middle ear (known as "glue ear" in children
- blockage of the outer ear by wax
- damage to the eardrum by infection or an injury
- otosclerosis, a condition in which the tiny bones of the middle ear (the ossicles) which normally move to transmit sound become immobile
Sensorineural hearing problems can include:
- age-related hearing loss – known as presbyacusis
- noise exposure
- infections caused by viruses – such as mumps, measles or rubella
- certain medications that are toxic to the ear other conditions such as non-cancerous growths that affect the auditory nerve or Meniere’s disease
Presbyacusis progresses gradually and tends to affect both ears equally, although you may not notice it for quite a few years.
The signs may be subtle at first, usually people notice having problems hearing speech clearly and this is due to the loss of hearing the high frequency sounds like 'sh', 'k', 'p' and 'f' in everyday speech.
Children and women's voices tend to be higher pitched and so they may be the ones that initially become more difficult to understand. As presbyacusis progresses it is harder to tell the difference between similar sounds.
Hearing noises in the ears where there is no external sound source, known as tinnitus can sometimes be linked to hearing loss. If you experience tinnitus we recommend you see your GP.
What causes it?
Miniscule hair cells line the spiral walls of the cochlea. Sound waves travel through the outer sections of the ear to the cochlea, and the hair cells bend when they hit them. This movement produces electrical signals, which are sent via a nerve straight to the brain.
The brain interprets the electrical signals as sounds and that is how we hear. Presbyacusis is caused by the loss of these tiny hair cells from the inner chamber of the ear.
We have about 15,000 hair cells in each cochlea, and they play a vital part of the chain of events that enables us to hear.
Unfortunately, we tend to lose these over time with age and we cannot regenerate them once they are damaged.
Will everyone get it?
Most of us will lose some of our hearing as we get older because of presbyacusis. The main cause is wear and tear to delicate hair cells over time, but the following factors can play a part:
- regular exposure to loud noise
- history of middle ear disease
- if other people in your family have presbyacusis