Types of hearing loss

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Hearing loss generally develops slowly over many years; the effects become apparent only gradually. This makes it difficult for those affected to recognise that they are actually suffering from a hearing impairment. Relatives, friends or colleagues are often the first to realise that something is wrong. 

There are three main types of hearing loss which include sensorineural hearing loss, conductive hearing loss and mixed hearing loss.

Conductive hearing loss

Caused by disorders of the outer and/or middle ear. Sound simply isn’t conducted properly from the outer ear or middle ear to the inner ear. This may be due to physical obstructions e.g. wax build-up or abnormalities e.g. perforated eardrum or damaged and/or defective ossicles that reduce the normal entry of sound waves through the auditory system to the nerves in the inner ear. Some conductive hearing losses can be temporary and can possibly be rectified by medical intervention.

Possible causes: 

  • Blockage of the outer ear e.g. wax. (Click here to read about our earwax removal services)
  • Collection of fluid in the middle ear - 'glue ear' (otitis media with effusion). 
  • Middle ear infections (acute otitis media). 
  • Otosclerosis - a condition where the ossicles of the middle ear harden with calcium deposits and become less able to vibrate. 
  • Damage to the ossicles e.g. serious infection or head injury. 
  • Perforated eardrum - can be caused by an untreated ear infection, head injury or a blow to the ear, or from poking something in your ear! 


Sensorineural hearing loss

As the description suggests this combines two areas. Sensory hearing loss i.e. the fault lies within the inner ear and neural hearing loss which is related to failings with the auditory neural pathway. The inner ear is unable to properly transmit sound to the brain. The hair cells inside the inner ear (especially those for high frequency hearing) have withered due to age, noise, disease or medications and no longer pick up the nerve impulses properly.

This kind of loss is permanent, since hair cells do not re-grow and normally affects both ears. Sensorineural hearing losses affect our sensitivity to sounds as well as our ability to discriminate between sounds.

Possible causes: 

  • Age-related hearing loss (presbyacusis) - This is a natural decline in your hearing. Many people get this as they get older because of damage to the hair cells in the cochlea.  See the video below about age-related hearing loss, as featured on Channel 4's Embarrassing Bodies Programme.
  • Damage to the hair cells by loud noises (acoustic trauma). This is more likely to happen if you work in a noisy place. 
  • Genetics - Approx. one in every thousand babies are born with a moderate to profound hearing loss. Genetic factors are thought to be the cause of at least half of these cases. 
  • Medication - Many routine prescribed drugs can cause Ototoxicity which in turn causes a permanent hearing loss, e.g. Quinine, aspirin, warferine and many more taken in high doses over time cause this damage.
  • Infections such as measles, mumps or meningitis. 
  • Ménière's diseas - causes hearing loss, dizziness and tinnitus (a persistent ringing in the ears). 
  • Certain cancer treatments - such as chemotherapy and radiation therapy, can cause hearing loss. 
  • Acoustic neuroma - This is a benign (non-cancerous) tumour affecting the auditory nerve causing deafness and tinnitus. 
  • Cholesteatoma (benign skin growth) in the middle ear, causing deafness and vertigo (sensation of movement when you're standing still). 

Mixed hearing loss

Quite simply where a patient presents with both a conductive hearing loss and a sensorineural hearing loss.