What are the types of hearing loss?
Adult hearing loss can be caused by a number of factors which can be broken down into two types; conductive hearing loss (problems where sound is prevented from being properly transmitted from the outer to the middle ear) and sensorineural hearing loss (problems between the inner ear and the brain itself). Sensorineural types of hearing loss are particularly more common with adults.
Conductive hearing loss results in an overall decrease in hearing function, whereas sensorineural hearing loss leads to problems with identifying complex sounds, such as picking speech out against background noise.
What causes conductive hearing loss?
- Infections in the middle and outer ear
- Build up of fluid in the inner ear
- Ostosclerosis – where the bones in the middle ear harden and can vibrate less
- Blockage of the outer ear – commonly by wax or a foreign body
- Damage to the ossicles (bones of the middle ear) – such as from an infection or head injury
- Perforated eardrum – can be caused by infection, head injury or by something being poked into the ear)
- Benign (non cancerous) tumours
What causes sensorineural hearing loss?
- Age related hearing loss – often due to damage of the hair cells in the cochlea
- Acoustic trauma (noise damage) – more common if you work in a loud environment
- Viral infections (e.g. mumps/measles) – but this is more common in children
- Diseases such as Ménière’s disease or multiple sclerosis
- Infections affecting the brain or meninges (brain covering) for example meningitis
- Acoustic neuroma – benign tumour affecting the auditory nerve
- Certain drugs which may be damaging to the auditory system
- Cancer treatments including radiation and chemotherapy
- Cholesteatoma of the middle ear – a benign skin growth which can lead to deafness and vertigo
What causes are most likely to affect me?
Of the causes listed, age related hearing loss is by far the most common, the RNID (Royal National Institute for Deaf People say approximately 42% of the 9 million people in the UK who have some level of hearing impairment are over 50 and 71% are over 70.