Common causes of hearing loss

Hearing problems can either be present at birth (congenital) or acquired at any age. It’s not always possible to determine why someone may be born deaf or develop deafness during their early years but the most common reasons are:

  • Genetic – more than half the children born deaf have an inherited gene defect [1].
  • Complications during pregnancy such as infections like rubella (German measles), cytomegalovirus (CMV), toxoplasmosis, and herpes.
  • Certain medicines that can damage a baby’s hearing system before birth.
  • Premature birth, which can make babies more susceptible to infections.

  • Severe jaundice (a liver condition).
  •  A lack of oxygen.
  •  Infections during early childhood, such as meningitis, measles or mumps.
  • Chronic ear infections in childhood such as otitis media, or glue ear.
  • A head injury.
  • Exposure to loud noise.
  • Ageing

How to reduce your risk of hearing loss

At any age:

See your GP if you or your child shows signs of an ear infection as complications from infections can lead to damaged hearing. Signs include:

  • A high temperature.
  • Severe earache that doesn’t clear up within a few days.
  • Discharge from the ear.
  • A severe sore throat.
  • Swelling around the ear.
  • Vomiting.
  • Hearing loss.
  • Don’t poke things such as cotton buds or fingers into your ear – it can cause damage as well as pushing bacteria and debris further down the ear canal, increasing infection risk.
  • Protect your hearing from prolonged and loud noise exposure. Over time, this can lead to noise-induced hearing loss.

In pregnancy and the early years:

  • Don’t smoke and avoid drinking alcohol – research suggests both may affect the development of the cochlea in the inner ear of your child.[2].
  • Avoid prolonged exposure to noise – at 20 weeks of pregnancy, your baby is able to hear noise.
  • Do your best to avoid infections. Wash your hands frequently to avoid infections with cytomegalovirus, a common herpes virus, which if passed to your baby during the first three months may cause hearing loss.
  • If you haven’t had rubella (German measles) or been vaccinated against it, avoid contact with anyone who has the infection. If passed from mother to baby during pregnancy, it can lead to complications for the baby including deafness. However it’s now very rare in the UK.
  • Make sure your child has the vaccinations routinely offered on the NHS. Complications from certain childhood infections can result in hearing impairment.

Noise-induced hearing loss

After age-related hearing loss, research shows that exposure to loud noise is the second most common cause of permanent hearing loss in the world.[3] But unlike age-related hearing loss, it’s avoidable. Noise-induced hearing loss can happen at any age but the damage often begins in teenage and adult years.

How it happens

Excessive noise can damage and destroy the sensory hair cells in the inner ear. We are born with around 17,000 hair cells. Once they are damaged, our body is unable to replace or regrow them. As a result, this type of hearing loss is permanent.

There are two main causes of noise-related hearing loss:

  1. Repeated exposure to loud noise over time, for instance from loud music or noise at work. The loss will be similar in each ear and will get worse with continued exposure. Unfortunately, many people don’t notice the effects for several years.
  1. Acoustic trauma – This occurs after exposure to a very high sound level for a short time, such as an explosion, and can cause a sudden hearing loss. It’s also usually sensorineural but it’s often worse in the ear nearest to the sound. However, if hearing loss as a result of acoustic trauma is caused by a perforated eardrum, it may heal and hearing may recover to a certain extent.

The most common causes of noise-induced hearing loss

Hearing loss is caused not only by the volume of the noise but also the length of time you’re exposed to it. Exposure to noise at or above 85dB (heavy city traffic) for eight hours can cause hearing loss. The louder the sound, the less time it takes to damage hearing. Common causes include loud music, for instance from personal stereos, rock concerts and night clubs as well as power tools, jet engines, motorcycles, sirens and work-related noise, such as in factories or on construction sites.

Protect your hearing at leisure

  • Be noise-aware – if you have to shout over noise to be heard by someone an arm’s length away, the noise is too loud.
  • Wear earplugs at concerts or in other noisy environments. Don’t worry – you’ll still be able to hear the music.
  • Choose headphones rather than ear buds – headphones better isolate background noise so you can listen at a lower volume. Also, with headphones, there’s more space between the source of sound and your inner ear.
  • If your personal stereo has a volume warning that pops up when it’s too loud, use it.
  • Set the volume of your personal stereo when you’re in a quiet environment. If you have to turn it down to have a conversation, then it’s too loud. More than 12 in 100 kids between the ages of six and 19 suffer from hearing loss as a result of using earphones at too a high volume[4].
  • Don’t fall asleep while listening to  music on your personal stereo  – exposure for hours at a time increases risk of damage.
  • Give your ears a rest. If you’ve been to a nightclub, avoid listening to loud music the next morning.
  • Be alert to ringing ears – this is a sign that your hearing has been put under strain. If this happens frequently, you’re risking permanent hearing damage.

Protect your hearing at work

If you’re in a noisy job, make sure you’re protected. By law, if the daily noise level reaches 80 dB, your employer is legally bound to start taking action.

For more information, visit the Health and Safety Executive’s website at http://www.hse.gov.uk/noise/

Age-related hearing loss

The medical term for age-related hearing loss is presbycusis. Typically, it’s a sensorineural hearing loss that affects both ears and gradually gets worse as more of the inner ear’s sensory hair cells become damaged or die.

Exposure to loud noise as well as certain conditions that are more common with age, such as high blood pressure or diabetes, and the side effects of certain medication including some chemotherapy drugs, can contribute to the problem.

Initially, age-related hearing loss starts with high-frequency sounds, making it difficult to understand conversations in noisy environments such as restaurants. Over the years, everyone’s hearing deteriorates. Because it happens slowly and gradually, most people don’t notice it for some time. On average, people put off seeking help for 10 years!

Ways to help communication

Learning a few techniques will help you communicate better with someone with hearing loss:

  • Don’t talk at length until you’ve got the person’s attention.
  • Face them so they can watch your lips and pick up clues from body language. This way sound will travel in the right direction.
  • Keep environments well lit so the person can see the others’ faces for speech cues.
  • When talking, try to keep your hands away from your face and don’t talk while eating.
  • Speak clearly and at a normal rate, pronouncing words normally. If the other person can’t understand what you’ve said after a couple of times, rephrase it.
  • Sit close to the affected person, so you don’t have to shout as shouting actually distorts sound.
  • If possible, move to a quiet place or switch the TV on to mute in order to cut out background noise. When booking a restaurant, ask for a quiet table.
References:

[1] Smith, RJH, Deafness and Hereditary Hearing Loss Overview, Last Revision: January 9, 2014. GeneReviews® [Internet], http://www.ncbi.nlm.nih.gov/books/NBK1434/
[2] Weitzman M, Govil  Maternal prenatal sming and hearing loss among adolescents. JAMA Otolaryngol Head Neck Surg.2013 Jul;139(7):669-77.

[3] http://www.hear-it.org/About-www-hear-it-org Accessed 19 June 2015

[4] World Journal of Otorhinolaryngology 2013 August 28; 3(3): 58-7