Deafness - Causes of hearing loss

Age and loud noises are the most common causes of hearing loss.

Age

Age is the biggest single cause of hearing loss. Hearing loss that develops as a result of getting older is often known as age-related hearing loss or presbycusis.

Most people begin to lose a small amount of their hearing when they are 30 to 40 years old. This hearing loss increases as you get older. By the age of 80 most people will have significant hearing problems.

Age-related hearing loss occurs when the sensitive hair cells inside the cochlea (the coiled, spiral tube section of the inner ear) gradually become damaged or die. This type of hearing loss is known as sensorineural hearing loss (see below).

As your hearing starts to deteriorate, high-frequency sounds, such as female or children’s voices, may become difficult to hear. It may also be harder to hear consonants. This can make understanding speech in background noise very difficult.

Loud noises

Another common cause of hearing loss is damage to the ear due to repeated exposure to loud noises over time. This is known as noise-induced hearing loss and it occurs when the sensitive hair cells inside the cochlea become damaged (known as sensorineural hearing loss).

People who are at a particularly risk of developing noise-induced hearing loss include:

• people who work with noisy equipment, such as pneumatic drills or compressed-air hammers
• people who work in environments where there is loud music, such as nightclub staff
• people who regularly listen to music at a high volume through headphones

Hearing loss can also occur suddenly due to an exceptionally loud noise, such as an explosion. This is known as acoustic trauma.

See preventing hearing impairment for advice about reducing your risk of noise-induced hearing loss.

Other types of sensorineural hearing loss

Sensorineural hearing loss occurs if the sensitive hair cells inside the cochlea are damaged, or as a result of damage to the auditory nerve (the nerve that transmits sound to brain). In some cases, both may be damaged.

Hearing loss caused by age and exposure to loud noises are both types of sensorineural hearing loss.

Sensorineural hearing loss can also be caused by:

• genetic hearing loss – some people may be born deaf or become deaf over time due to a genetic abnormality, although there is not always a family history
• viral infections of the inner ear, such as mumps or measles
• viral infections of the auditory nerve, such as mumps or rubella
• Ménière's disease – where a person suffers with vertigo (spinning dizziness), hearing loss which can come and go, tinnitus and a feeling of a blockage in the ear
• acoustic neuroma – a non-cancerous (benign) growth on or near the auditory nerve
• meningitis – an infection of the protective membranes that surround the brain and spinal cord
• encephalitis – inflammation of the brain
• multiple sclerosis – a neurological condition affecting the central nervous system (the brain and spinal cord)
• stroke – where the blood supply to the brain is cut off or interrupted

Some medications, such as certain chemotherapy medicines and certain antibiotics can also damage the cochlea and the auditory nerve, causing sensorineural hearing loss.

Sensorineural hearing loss is permanent and hearing aids are often required to improve hearing in these cases. Read more about treating hearing loss.

Conductive hearing loss

Conductive hearing loss occurs when sounds are unable to pass into the inner ear. This is usually due to a blockage, such as having too much ear wax, a build-up of fluid in the ear (glue ear), or an ear infection.

Conductive hearing loss can also be caused by:

• a perforated eardrum – where the eardrum is torn or has a hole in it
• otosclerosis – an abnormal growth of bone in the middle ear which causes the inner hearing bone (the stapes) to be less mobile and less effective at transmitting sound
• damage to the hearing bones from injury, a collapsed ear drum or conditions such as cholesteatoma (an abnormal collection of skin cells inside your ear)

Conductive hearing loss is usually temporary and it can often be treated with medication or minor surgery. Read more about treating hearing loss.