Sensorineural Hearing Loss

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Sensorineural hearing loss involves damage to the tiny hair cells that are activated by sound waves, to vibrate and release chemical messages that stimulate the auditory nerve. The auditory nerve is made up of many nerve fibres, which carry signals to the brain where they are interpreted as sound. While sensorineural hearing loss usually involves damage to the tiny hair cells, it also can result from damage to the auditory nerve.

A sensorineural hearing loss reduces the intensity of sound.  Sensorineural hearing loss can also distort what is heard, even when the sounds are clear enough. People with sensorineural hearing loss often struggle to hear words clearly, particularly certain consonant sounds, when in noisy environments. 

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Most sensorineural hearing loss cannot be reversed with medical treatment and is typically described as an irreversible, permanent condition. Nevertheless, research into a cure continues. Once any underlying medical conditions have been ruled out or addressed, most people with sensorineural hearing loss can benefit from hearing aids.

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Some of the potential causes of sensorineural hearing loss include:

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• Exposure to loud noise

• Ageing (presbycusis)

• Medicines that damage the ear (ototoxic)

• Illnesses, such as meningitis, measles and certain auto-immune disorders

• Genetics that is, hearing loss runs in the family

• Trauma to the head

• Structural malformation of the inner ear

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Conductive Hearing Loss

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Conductive hearing loss is mechanical in nature. That means that something, a physical condition or disease is stopping sound from being conducted from the outer or middle ear to the inner ear, where nerves are stimulated to carry sound to the brain.  Often, the cause of conductive hearing loss can be identified and treated. Medical treatment of conductive hearing loss frequently allows for partial or complete improvement in hearing. Hearing aids are then often helpful in compensating for any remaining hearing loss.

 

Potential causes of conductive hearing loss include:

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• Wax buildup

• Fluid in the middle ear due to colds or allergies

• Fluid in the middle ear due to poor eustachian tube function (eustachian tube drains fluid from the middle ear and ventilates it to regulate air pressure there)

• Ear infection

• A foreign object lodged in the ear

• A ruptured eardrum (also called a perforated eardrum or a tympanic membrane perforation), which means there is a tear in the membrane that separates the outer ear from the middle ear

• Structural malformation of parts of the ear (Anotia, Microtia or Otosclerosis)

• Cholesteatoma, developing as a cyst or sac that sheds layers of old skin.

• Trauma to the ear or dislocation of the middle ear bones

• In rare cases, tumours.