Causes of hearing loss

The external ear (pinna or auricle) can be damaged by trauma or inflammation. There can also be a congenital abnormality (present at birth). Noticeable hearing loss will only arise if the entrance to the ear canal is obstructed or closed preventing sound entry.

Any blockage in the ear canal prevents sound transmission. Excessive wax is the most common cause of hearing loss.

For more information about looking after your ears or to find a professional earwax removal specialist, visit the Blocked Ears website run by the Association of Independent Hearing Healthcare Professionals.

Swelling in the ear canal due to allergy, skin infection or inflammation is called otitis externa (or swimmer’s ear).

Foreign bodies in the ear canal can block the passage of sound.

Although not usually sufficiently large to cause hearing loss, bony growths can develop in the ear called osteoma. If one or more of these grow to sufficient size, surgical intervention may be necessary to avoid hearing loss and other complications.

The eardrum is vulnerable to perforation and subsequent infection if anything is pushed too far into the ear canal e.g. cotton buds. Perforations of the eardrum are usually due to middle ear inflammation/infection (otitis media) usually resulting in a discharge from the middle ear into the ear canal as well as hearing loss. A blow to the side of the head, especially against the pinna, can cause the eardrum to rupture.

Otitis media is the most common form of middle ear hearing loss caused by problems with the health and function of the eardrum and ossicular chain. This is a particular problem in young children but can also affect adults.

A healthy middle ear cavity is filled with air and is ventilated by a narrow tube (the Eustachian tube) between the middle ear and the back of the nose.

Nasal congestion caused by colds or infections can prevent the Eustachian tube from supplying air to the middle ear and draining any fluid which encourages middle ear inflammation and infection (otitis media).

Cholesteatoma is a benign growth which starts within a retracted section of the eardrum resulting from a sustained, abnormal middle ear pressure. It gradually enlarges, not only resulting in hearing loss but, if left untreated surgically, it can be life-threatening from complications such as mastoiditis and meningitis.

Any abnormal pressure in the middle ear cavity, due to inadequate ventilation and drainage of the middle ear cavity, can put the eardrum under such stress that it perforates. Barotrauma is significant atmospheric pressure changes, such as when flying or diving, can cause pain and hearing loss sometimes resulting in eardrum rupture (called barotrauma).

The chain of three tiny bones in the middle ear is known as the ossicles or ossicular chain. These tiny bones can suffer dislocation due to head trauma such as a road traffic accident or contact sports such as boxing or rugby.

Apart from the effects of middle ear inflammation and infection, the most common condition affecting the ossicular chain in adults is otosclerosis. Otosclerosis is a hereditary condition, but it doesn’t appear in every generation of an affected family.

Hearing loss usually becomes noticeable before the middle years of adulthood but is highly variable in onset. Otosclerosis can be successfully treated surgically but, for those who do not wish to have surgery or where surgery is only partially successful, hearing aids are usually very effective.

The effects of ageing are numerous. Age-related hearing loss is called presbyacusis and affects the majority of those over 60 years of age. It’s the most common cause of hearing loss.

All parts of the auditory system are affected by ‘wear and tear’ but particularly the cochlea and its associated nerve pathways to the brain. In its earlier stages, it affects hearing sensitivity to higher-pitched sounds such as understanding speech especially when there is background noise.

Ageing can also mean that the auditory nerve and hearing centres in the brain can lose the ability to process sound efficiently causing problems with more complex sounds such as speech or music.

Tinnitus is also frequently experienced.

Exposure to excessive noise damages the delicate sensory cells in the cochlea (called hair cells). The higher the noise level or the longer the duration of exposure, the greater is the likelihood of permanent hearing loss often with tinnitus.

Examples of noise exposure that can damage hearing include noise damage from listening to loud music using earbuds, occupation-related noise or loud music at concerts.

For more information about protecting your hearing in noisy environments, visit the UK Hearing Conservation Association website. 

Cardiovascular disease is a significant component in age-related hearing loss. However, it can affect a person of any age when the blood supply to the inner ear or hearing centres in the brain is significantly reduced or stops altogether.

The cochlea in the inner ear is highly sensitive to a reduction in blood supply which can cause irreversible damage. Hardening of the arteries (arteriosclerosis), high blood pressure, thrombosis, stroke and heart attack can all result in hearing loss which is usually permanent.

There are many infectious diseases, bacterial and viral, which can cause sensorineural hearing loss with some of them affecting one ear only. Although not a full list, the more common ones are measles, mumps, meningitis, chicken pox, shingles and influenza.

Some medications are known to cause sensorineural hearing loss, and these are called ototoxic drugs. These are only used for life-threatening conditions such as certain cancers or serious infections. Aspirin can cause hearing loss if taken in regular, larger doses but usually the hearing loss is reversible once the medication is stopped.

Research studies have shown that fearing loss is twice as common in adults with diabetes than those without. Diabetes can cause sensorineural hearing loss, and it is encouraged that people living with diabetes undergo regular hearing checks.

For more information and research on the links between diabetes and hearing loss, visit Diabetes.co.uk global community website. 

Meniere’s is a long-term, progressive vestibular condition that affects the hearing parts of the inner ear and the balance systems. Usually only one ear is affected, but it can affect both ears.

Symptoms include sudden or acute attacks of dizziness, vertigo, fluctuating hearing loss and low-pitched tinnitus. These can last anywhere from a few minutes to 24 hours or more.

For further information about this condition, visit the Meniere’s Society website.

Genes are involved in the development of our ears and hearing. Hearing loss can be inherited or passed down through generations of families. However, genetic changes to hearing can also occur, even if there is no family history of deafness or if a person is not born with it. Genetic hearing loss can have a late onset such as in Ushers Syndrome which involves progressive loss of both vision and hearing.

Although very unusual, a tumour can develop between the inner ear and the brainstem. It’s a benign rather than malignant tumour (cancerous) called an acoustic neuroma or vestibulocochlear schwannoma.

It normally grows very slowly, gradually compressing the auditory nerve and may also affect the nearby vestibular (balance) nerve so that there is both hearing loss and balance problems, often with tinnitus.

The tumour is typically on one side, so anyone found to have sensorineural hearing loss and/or tinnitus just in one ear should see their GP for referral to an ENT Consultant for specialist assessment.

Bilateral tumours are even rarer and are usually associated with a hereditary condition called Neurofibromatosis Type 2 (NF2).

Dementia’s links to untreated hearing loss are still being researched. It is not yet fully understood how untreated hearing loss can accelerate the onset of cognitive decline and dementia. It is encouraged to seek professional help for hearing loss when the changes in hearing are first noticed.

For further information about dementia and its linked with hearing loss, visit the Alzheimer’s Society website for further information.