TYPES OF HEARING LOSS
Hearing loss can be permanent or temporary depending on the cause.
Ageing, noise exposure, wax, glue ear, viral infections and perforated ear drums can all be responsible for a reduction in hearing.
I have outlined below the four different types of hearing loss below.
Sensorineural Type Hearing Loss
Sensorineural hearing loss is caused by a problem with the INNER part of the ear. The cochlea or the auditory nerve.
The cochlea is a snail shell shaped structure which contains thousands of tiny hairs resting on hair cells.
If this structure was spread out it would resemble a piano keyboard with hair cells at one end responding to low frequency sounds and hair cells at the other responding to high frequency sounds.
These tiny hairs, when stimulated by sound vibrations, initate electrical impulses in the auditory nerve (the nerve which carries information from the ear to the brain where it is experienced as sound).
Ageing, noise exposure, certain medications and viral infections are common causes of sensorineural type hearing loss.
Common to this type of loss is a loss of 'sensitivity' to sounds and also a loss of 'clarity'. Sometimes there is also a 'difficulty tollerating loud sounds'.
A high frequency hearing loss is where the person has lost hearing in the higher frequencies but with low frequency hearing remaining normal. In this case the person will experience hearing low frequency parts of words (vowel sounds) quite well.
The higher frequency parts of words the 'ssss 'and' f,' sounds are not heard well. Unfortunately, it is the higher frequency parts of words which are most important for understanding speech. (Speech clarity).
Hearing aids can usually significantly help most people with a sensorineural hearing loss.
Conductive Type Hearing Loss
A Conductive type hearing loss is caused by a problem with the outer and / or middle part of the ear.
Conductive hearing loss can be caused by wax, fluid in the middle ear, glue ear, a perforared ear drum or any problem that can effect -
'the conduction of sound'
Conductive hearing loss cause a reduction in sensitivity to sound.
Usually by increasing the volume of the sound the person with a conductive hearing loss can hear quite well.
Conductive type hearing loss may be treatable by surgery or medication and may not be permanent.
Mixed Type Hearing Loss
A mixed type hearing loss involves elements of both a conductive and sensorineural type loss. For example a person may have a perforated ear drum (a conductive type loss) but may also have an underlying sensorineural type loss due to age and noise exposure.
Usually, it is only the conductive element to the hearing loss that may be improved by treatment or surgery from a medical professional.
Central Type Hearing Loss
A Central Type hearing loss is caused by any problem that can effect the brains ability to process sounds.
Central hearing loss can result from ageing, neurological disorders or brain injury. The person's ability to perform basic and complicated auditory tasks may be affected.
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