What Is the Most Common Etiology of Hearing Impairment?

Hearing impairment (dysaudia) refers to the qualitative or functional abnormalities of the various levels of nerve center generators in the auditory system, including sound transmission, sensory sounds, and comprehensive analysis of sounds, which cause hearing loss to varying degrees. Habits are called deafness. Only severe hearing loss is called deafness, which is manifested in that the patient cannot hear any words in both ears. Hearing loss that does not reach this level is called hearing loss.

Basic Information

nickname: Deafness, hearing loss
English name: dysaudia
English alias: deafness, hearing loss
Visiting department: ENT

Common locations: ear
Common causes: Genetic, viral or bacterial infections, ototoxic drugs, deafness factors such as head trauma and radiation, drugs and chemicals, noise, trauma, etc.
Common symptoms: Tinnitus, hearing allergies, deafness, hallucinations, and hearing loss

Causes of hearing impairment

Genetic factor

Sensorineural deafness caused by genetic factors is mostly severe or very severe.

2. Environmental factors

Includes deafness factors such as mother's pregnancy, various viral or bacterial infections during or after birth, ototoxic drugs, head trauma, and radiation.

3. Deafness caused by drugs and chemicals

Drug-induced deafness: Deafness caused by aminoglycoside antibiotics is one of the main causes of hearing-impaired children in China. Chemical preparations: Some industrial preparations such as lead and mercury damage the hearing organs, carbon monoxide poisoning causes hemoglobin oxygen-carrying disorders, and nerve hypoxia will affect the auditory system, especially for children.

4. Noise Deafness

More common in adults, rare in children. Hearing of bilateral or unilateral high-frequency hearing loss.

5. Trauma

Children are active and prone to trauma and deafness.

Hearing impairment clinical manifestations

The common clinical symptoms of hearing impairment include tinnitus, hearing allergies, deafness, auditory hallucinations, and hearing freak.

Hearing impairment

The purpose of a hearing test is to understand the extent, nature, and location of the hearing loss. There are many inspection methods, which can be summarized into two categories:

Objective inspection method

Auditory brainstem evoked response threshold, auditory brainstem evoked response latency, steady state evoked response, acoustic impedance test, aberrant otoacoustic emission, cochlear electrogram This test method is not affected by age, mental state. The results are more accurate and reliable.

(1) Learn about hearing by observing unconditioned reflexes caused by acoustic stimuli (such as blinking eyes, turning heads, limb movements, etc.);

(2) Checking hearing by establishing conditioned reflex or habitual response (such as skin resistance audiometry, diorama audiometry, etc.);

(3) Checking hearing using biophysical methods (such as acoustic impedance-admittance audiometry);

(4) Use neurobiological methods to check hearing (eg cochlear electrogram, auditory brainstem response).

2. Subjective inspection method

This method is convenient and fast, such as whispering inspection, stopwatch inspection, tuning fork inspection, audiometer inspection, pure tone audiometry, directional reflex measurement, and speech recognition rate test. However, due to many factors such as young age, mental and psychological disorders, the correct audiometry conclusions can be affected.

Hearing impairment diagnosis

1. Graded by hearing loss

The International Health Organization (WHO-1997) rates hearing loss based on average hearing loss at 500Hz, 1000Hz, 2000Hz, and 4000Hz as follows:

25dBHL normal hearing;

26 40dBHL mild deafness;

41 60dBHL moderate deafness;

61 80dBHL severe deafness;

Very severe deafness above 81dBHL.

2. Classified by the location of deafness

(1) Conductive deafness Where conductive lesions are confined to the outer and middle ears and affect the sound guidance function, they are all conductive deafness. For example, developmental deformities of the outer and middle ears, obstructive diseases of the external ear canal, inflammatory or non-inflammatory diseases of the middle ear, and ear sclerosis can all cause conductive hearing loss.

(2) Sensorineural deafness directly affects various lesions of peripheral receptors, auditory nerve conduction pathways and the auditory center, which can cause sensorineural deafness. Sensorineural deafness can be divided into the following three types: Cochlear deafness: Cochlear deafness is the disease that is limited to the cochlea and affects its sensory function. Neurogenic hearing loss: Neuropathic hearing loss occurs when the lesion directly affects the median ganglia or occurs on the auditory nerve pathway. Central deafness: The lesions are located in the brainstem and brain, and cause central deafness when the cochlear nucleus and its central conduction pathway are involved.

(3) Middle ear lesions coexist in mixed deafness , and hearing impairment caused by sound wave transmission and feeling is called mixed deafness. The cause of mixed deafness can be a disease that simultaneously damages the ear's sound and sensory systems, or it can be caused by different diseases that cause dysfunction of the middle ear and inner ear or the auditory pathway.

3. Classified by time of illness

(1) Congenital deafness includes epigenetic deafness, congenital atresia of the ear canal, malformation of the middle or inner ear, and various types of deafness caused by pregnancy and perinatal period.

(2) Acquired deafness includes various types of conductive deafness in the outer and middle ears, such as acquired congenital atresia of the external ear canal, suppurative otitis media, tumors in the external ear and middle ear, various trauma and otosclerosis, etc .; Including various sensorineural deafness caused by various infectious diseases, drug-induced deafness, labyrinthitis, auditory neuroma, auditory neuropathy, and functional deafness caused by mental factors.

Hearing Impairment Treatment

Conductive deafness

(1) Conservative treatment of this condition refers to conductive deafness caused by various inflammations, mainly antibiotics, which can be subsided by intravenous drip or local drip, and hormones and antihistamines can also be applied. Reduce exudation and restore hearing as quickly as possible.

(2) Surgical treatment of conductive deafness is mainly surgery. Hearing can be restored through different surgical methods for external and middle ear deformities, various oppressive eustachian tube diseases, and ear trauma. Bone conduction hearing aids or vibration sound bridges and bone anchored hearing aids can also be considered in children with external middle ear deformities.

2. sensorineural hearing loss

(1) Drug treatment . While excluding or treating the primary disease, as soon as possible, drugs that can dilate the inner ear blood vessels, reduce blood viscosity and dissolve small thrombus, glucocorticoids, B vitamins, energy mixtures, etc. can be used as necessary Application of antiviral and antibacterial drugs.

(2) Children with hearing aid hearing loss 80dB are recommended to choose hearing aids and perform hearing and speech rehabilitation training in parallel.

(3) Cochlear implants are currently a good tool to help severely and severely deaf people gain hearing and gain or maintain speech function. Cochlear implantation is recommended for children with hearing loss> 80dB, and hearing and speech rehabilitation training should be performed concurrently.

3. Mixed deafness

Perform middle ear treatment first. If the effect is not good, you can consider optional hearing aids and perform hearing and speech rehabilitation training in parallel.

Hearing Impairment

1. Avoid using ototoxic drugs

Clinically, drugs should be used rationally, and ototoxic drugs such as streptomycin and other aminoglycoside antibiotics should be avoided.

2.Early treatment may cause deafness

(1) Treatment of systemic diseases For basic systemic diseases that may cause deafness, such as hypertension, diabetes, and kidney disease, it is necessary to control and rationally use drugs to avoid affecting hearing function.

(2) Treatment of local diseases For common ear diseases that cause deafness, such as chronic suppurative otitis media, chronic secretory otitis media, otosclerosis, and sudden deafness, active treatment should be performed to avoid causing hearing impairment.

3. Do a good job of protecting relative noise

It is very important to avoid prolonged exposure to noisy environments and prolonged susceptibility to noise-induced deafness such as wearing headphones. In addition, people who work in noisy environments should pay attention to occupational protection and regularly review the individual's hearing.