What are the types of hearing loss?
Hearing loss is not generalized, but there are three major categories, and different types of hearing loss, there are different causes, and clinical treatment methods are also different.
The way the sound is transmitted into the cochlea mainly includes two ways. One is the transmission of the acoustic signal through the air, through the external auditory canal, through the middle ear and the inner ear as the airway; the other is that the sound source directly vibrates the skull and transmits the acoustic signal. Into the inner ear, did not go through the external auditory canal and middle ear, for the bone conduction pathway. Therefore, pure tone audiometry can be performed by using different acoustic energy conversion devices for air conduction (using a head-mounted or insertable earphone) and bone conduction (using a bone oscillator), and the clinician compares the presence of the air conduction threshold and the bone conduction threshold. Differences determine the type of hearing loss.
(1Conductive hearing loss
If the pure tone hearing threshold measurement report shows that the bone conduction threshold is normal at each frequency, the air conduction threshold is increased, and the difference between the two is ≥15dBThen, the patient is determined to have conductive hearing loss. Common in the external auditory canal and/Or patients with abnormal middle ear, such as external ear canal osteoma, secretory otitis media, middle ear cholesteatoma, otosclerosis.
(2Sensorineural hearing loss
If the pure tone hearing threshold measurement report shows that the air conduction and bone conduction thresholds of each frequency are increased, which is greater than the normal range, and the difference between the two is <15dB, is the sensorineural hearing loss. Common in the inner ear abnormalities and/Or patients with abnormal nerve conduction pathways.
(3Mixed hearing loss
If the pure tone hearing threshold measurement report shows that the air conduction and bone conduction thresholds of each frequency increase, which is greater than the normal range, and the difference between the two is ≥15dB, is a mixed hearing loss. Such patients have external auditory canal and/Or the middle ear is abnormal, the inner ear and/Or there is an abnormality in the auditory nerve conduction pathway.
3What are the levels of hearing loss?
Currently, according toWHOorganization1997According to the standard released in the year, the degree of hearing loss can be divided into four levels according to the pure tone threshold measurement (average hearing threshold), which are light, medium, heavy and extremely severe, as shown in the following table.
Average hearing thresholddBHL）
Hearing loss degree Graded patient performance
26-40 Mild Small sound is difficult to distinguish
41-60 Moderate When listening to everyday speech, it is difficult to hear and hear, and listening to other people is unclear.
61-80 Severe Difficulty listening to a loud conversation
≥81 Extremely severe I can’t just rely on listening and people to communicate, I need help with lip reading and body language.
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