Etiology of deafness
1.Classification of deafness according to the site of occurrence
(1) Conductive deafness: Any lesion confined to the outer and middle ear and affecting the conductive function is considered conductive deafness. For example, developmental malformations of the outer and middle ears, obstructive diseases of the outer ear canal, inflammatory or non-inflammatory diseases of the middle ear, and otosclerosis can all cause conductive hearing loss.
(2) Sensorineural deafness: All kinds of lesions that directly affect the terminal receptors, the auditory nerve conduction pathway and the auditory center can cause sensorineural deafness. The following three types of sensorineural deafness can be identified: Cochlear deafness: Any lesion that is confined to the cochlea and affects its sensorineural function is considered cochlear deafness. Neurological deafness: Any lesion that directly affects the spiral ganglion or occurs in the auditory nerve conduction pathway is considered neurological deafness. Central deafness: Central deafness results when the lesion is located in the brainstem or brain and involves the cochlear nucleus and its central conduction pathway and the auditory cortical center.
(3) Mixed deafness: Hearing impairment caused by the simultaneous presence of lesions in the middle and inner ear that affect the conduction and perception of sound waves is called mixed deafness. The cause of mixed deafness can be a lesion that damages both the sound transmission and perception systems of the ear, or it can be caused by different diseases that cause dysfunction of the middle and inner ear or the hearing conduction pathway respectively.
2. Classification according to the time of disease
(1)Congenital deafness: including congenital atresia of the external auditory canal, malformation of the middle or inner ear, and various kinds of deafness caused during pregnancy and perinatal period.
(2) Acquired deafness: including all kinds of conductive deafness in the outer ear and middle ear, such as acquired atresia of the external auditory canal, suppurative otitis media, tumors of the outer ear and middle ear, various traumas and otosclerosis; among sensorineural deafness, including all kinds of sensorineural deafness caused by various infectious diseases, drug intoxication deafness, labyrinthitis, auditory neuroma, auditory neuropathy, senile deafness and functional deafness caused by mental factors.
Clinical manifestations
The common clinical symptoms of auditory disorders include tinnitus, auditory hypersensitivity, deafness, phantom hearing, and auditory loss.
Examination
The purpose of audiological examination is to understand the degree, nature and location of the hearing loss. There are many methods of examination, one is to observe the patient’s subjective judgment and response, called subjective observation method of hearing, such as whispering, stopwatch examination, tuning fork examination, audiometer examination, etc., but this method can often be due to the age of too young, mental and psychological state disorders and other factors that affect the correct audiometric conclusions. Another category is not required to make a subjective judgment response to acoustic stimuli, can objectively determine the hearing function, called the objectively observed hearing method, the results are more accurate and reliable, there are the following.
1, through the observation of unconditioned reflexes caused by acoustic stimuli to understand hearing (such as transient eyes, head turning, physical activity, etc.);
2.Checking hearing by establishing conditioned reflexes or habitual responses (e.g. skin resistance audiometry, western mirror audiometry, etc.);
3.Checking hearing by biophysical methods (e.g. acoustic impedance and conductance audiometry);
4.Checking hearing by neurobiological methods (e.g. cochlea electrogram, auditory brainstem response).
Diagnosis
A clear diagnosis can be made by clinical manifestations, cerebrospinal fluid examination, other necessary selective auxiliary tests including blood routine, blood electrolytes, blood glucose, urea nitrogen, etc., skull base radiographs, cranial CT and MRI examinations, genetic deafness gene examination, otorhinolaryngological examination and audiological examination.
Treatment
1.Treatment for the cause
(1) Central deafness caused by pediatric brain injury: The lesion is located in the brainstem and brain, and causes central deafness when it involves the snail nucleus and its central conduction pathway and the auditory cortical center. Early stage can be treated with locus plus acupuncture point drug injection with significant efficacy.
(2) If antibiotics and surgical treatment are applied to patients with otitis media complicated by vagal inflammation; deafness due to cerebral bridge cerebellar horn tumor should be treated surgically; deafness due to drug intoxication should be stopped immediately. Intrathecal, ventricular and intracerebral pool injections of gentamicin and streptomycin should be avoided as much as possible.
2.Medication
B vitamins, vasodilators (niacin, dibazol, calcium channel blockers, etc.) should be given appropriately according to clinical manifestations.
3.Trial hyperbaric oxygen therapy can be carried out
Hyperbaric oxygen has a significant effect on the recovery of hearing and improvement of accompanying symptoms in patients with sudden deafness.
4.Wearing hearing aids can improve the hearing condition of patients.
5.For cochlear deafness, electronic cochlear implantation can be considered.
Prevention
1.Avoid the application of ototoxic drugs
Avoid ototoxic drugs such as streptomycin and other aminoglycoside antibiotics.
2.Early treatment of possible causes of deafness
(1) Treatment of systemic diseases The systemic underlying diseases that may cause deafness, such as hypertension, diabetes, and renal disease, should be controlled and reasonably administered to avoid involvement of hearing function.
(2) Treatment of local diseases Common ear diseases that cause deafness such as chronic suppurative otitis media, chronic secretory otitis media, otosclerosis and sudden deafness should be actively treated to avoid causing hearing impairment.
3.Protect yourself from relative noise
It is very important to avoid being in a noisy environment for a long time and wearing headphones continuously for a long time and other susceptibility factors that cause noise-related deafness. In addition, it is important for people who work in noisy environments to pay attention to occupational protection and regular review and testing of individual hearing.