Hearing loss is simply what happens when sound from the world around us isn’t communicated to the brain properly, for whatever reason. It can affect you in many different ways, but it can also be a difficult condition to navigate for your friends and family.
Understanding the causes of hearing loss can help you and your loved ones understand the condition.

Types of hearing loss

To understand what might be causing your symptoms, it is important to first understand the different types of hearing loss.

There are two main types of hearing loss: sensorineural hearing loss and conductive hearing loss.

Sensorineural hearing loss occurs due to abnormalities in the neural pathway that carries sound information to the brain (including the inner ear and auditory nerve), while conductive hearing loss is caused by soundwaves being blocked from passing through to the inner ear. This is usually due to blockages in the ear canal.

It is possible to have both types of hearing loss at the same time. This is known as mixed hearing loss.

Each type of hearing loss can be brought on by different factors.

What is the biggest cause of hearing loss?

Becoming hard of hearing is commonly associated with age, and this type of hearing loss — known as presbycusis — is the most common cause of hearing impairment. Presbycusis is a sensorineural type of hearing loss and occurs due to gradual damage to our ‘hearing cells’ over time.

These cells are tiny hairs in our inner ear that detect vibrations in the air (i.e. sound) that simply become worn out as we age. Usually, this type of hearing loss is initially quite mild, but can progress to being moderate and severe as we get older.

Presbycusis typically affects both ears equally, and those who have it often report that they find it more difficult to follow conversations, as higher pitches and tones become harder to hear. Soft sounds, such as ‘s’, ‘th’ and ‘f’ can also get lost in background noise.

Hearing aids are usually recommended for age-associated hearing loss, and many who use them report improvements both to their hearing and quality of life.

Common causes of sensorineural hearing loss

After ageing, exposure to sustained levels of excessive noise is the leading cause of damage to the inner ear.1 This is because the intensity of the loud sounds disrupts the tiny hairs and nerve cells in the inner ear. This disruption reduces the amount and quality of information that is sent to the brain. If the brain doesn’t receive all of the sound information from the ears, the result is hearing loss.

Other causes of sensorineural hearing loss include:

  • Ménière’s disease — an inner ear condition that is typically associated with tinnitus (ringing noise inside the ear), vertigo (room spinning), and hearing loss. This condition can cause hearing loss to come and go as it progresses
  • Brain injury or head trauma — trauma can cause the inner ear to rupture and to leak its fluid, which can impact hearing. It is sometimes possible to repair this damage through emergency surgery
  • Infections — viral infections can cause what is known as sudden sensorineural hearing loss (SSHL). These cases require urgent medical attention and are treated with a class of steroids known as corticosteroids
  • Ototoxic drugs — these types of drugs are damaging to the ear and can cause varying degrees of hearing loss, from ‘mild’ to ’profound’. If you have been advised to take any drug that is ototoxic, be careful not to take more than the recommended dosage and to speak to your GP about any side effects that occur. 2
  • Genetics — numerous genetic conditions are associated with hearing loss, with severity ranging from ‘mild’ to complete deafness. It is believed that there are over 400 types of genetic hearing loss. 3
  • Malformations of the inner ear — the inner ear is where you’ll find the organ for hearing (known as the cochlea). This is what helps to send sound signals to our brain to allow us to hear. Malformations in this area result in ‘severe’ to ‘profound’ hearing loss, usually in both ears. Cochlear implants may be recommended as treatment.
  • Otosclerosis — otosclerosis, or abnormal bone growth inside the ear, is a common cause of hearing loss in young people. It tends to begin in a person’s 20s with mild hearing loss that progresses with age.

Certain conditions, such as diabetes or conditions that involve your blood pressure, can also put you at a higher risk of developing sensorineural hearing loss.

Can diabetes cause hearing loss?

What's the link between blood pressure and hearing loss?

Common causes of conductive hearing loss

While a sensorineural hearing loss is a result of problems with the inner ear, a conductive hearing loss arises from issues with the middle and outer ear — usually, a blockage of some sort. Issues such as blockages in the middle ear can often reduce the amount of sound that is able to pass through to the inner ear and onto the brain. 

The severity of a conductive hearing loss depends on how blocked the ear is, but generally speaking, a conductive hearing loss tends to be less severe than sensorineural hearing loss. 

A conductive hearing loss is typically treated either with medicine or surgery. 

Common causes of conductive hearing loss include:

  • Earwax — the most common cause of conductive hearing loss. When earwax becomes impacted in the ear canal, it can prevent sound from easily passing through. This can be treated by removing the excess wax.
  • Ear infections — ear infections can occur in the middle ear (otitis media) or the outer ear (otitis externa). Symptoms can vary, but there is usually a build-up of fluid which causes a temporary reduction in hearing: sounds are usually quite muffled on the side of the infection. In some cases, it’s possible for ear infections to lead to permanent hearing loss, find out more here. Middle ear infections (otitis media) are the most frequently diagnosed disease among infants and young children, with 75% having had it by the time they are three years old.
  • Foreign bodies — this is more commonly seen in children. If there is a foreign object stuck in your ear, do not attempt to remove it yourself: seek medical help to prevent it from being pushed further inside. 
  • Fluid in the middle ear — this tends to be a reaction to minor ailments like hay fever and the common cold. It typically resolves as the ailment itself improves.  — when there is a hole in your eardrum, rather than a blockage. This reduces the clarity of sound being transmitted to the brain, therefore making it harder for you to hear. 

Common causes of mixed hearing loss

A mixed hearing loss refers to the experience of having both sensorineural (affecting the inner ear) and conductive (affecting the middle and outer ear) hearing loss at the same time. This can lead to more severe hearing loss than if you were affected by one type alone.

Mixed hearing loss often has more than one cause but can also occur when one factor affects the ear in different ways. For example, if you had a long-standing infection, then you might experience conductive hearing loss due to physical blockage. You might experience this alongside eventual sensorineural deafness as the infection affects the hair and nerve cells of the inner ear.

To prevent mixed hearing loss, it’s important to address the root causes of both the sensorineural and conductive hearing loss you are experiencing.

Learn more about hearing loss

Hearing loss can be a frustrating experience, but with accurate diagnosis and treatment, the majority of people are able to improve their hearing and get back to their daily lives as normal. Remember that most ear conditions are treatable and do not develop into long-term conditions. 

To learn more about hearing, ear health, and how to protect your hearing, visit our information hub on hearing loss. 

If you feel that you need to speak to an expert or are concerned about any aspect of your hearing or hearing loss, please don’t hesitate to get in contact with your local store or book an appointment.

You can also test your hearing for free using our online hearing test. 

References

1. HSE, ‘Noise induced hearing loss in Great Britain’, Health and Safety Executive, no date, [online], https://www.hse.gov.uk/statist... (accessed 16 July 2020) 
2. Bisht M, & Bist S.S., Ototoxicity: the hidden menace, Indian J Otolaryngol, Head Neck Surg. 2011;63(3):255-9.
3. Shearer A.E., Hildebrand M.S., Smith R.J.H., ‘Hereditary Hearing Loss and Deafness Overview’, in Adam M.P., Ardinger H.H., Pagon R.A., et al (ed), GeneReviews [internet], Seattle (WA): University of Washington, Seattle; 14 Feb 1999 [updated 27 July 2017], https://www.ncbi.nlm.nih.gov/b... (accessed 16 July 2020)  
4. Le saux N, Robinson J.L., Management of acute otitis media in children six months of age and older, Paediatr Child Health, 2016;21(1):39-50.

Understanding hearing loss
Treatment of hearing loss
Symptoms of hearing loss