There are many ways to classify deafness, and depending on the nature of the lesion, it can be divided into organic deafness, which has organic lesions of the auditory system, and functional deafness, which does not. Depending on the location of the lesion, it can be classified as conductive deafness, neurological deafness and mixed deafness. Depending on the time of onset, congenital deafness and acquired deafness can be classified. According to the cause, it can be divided into hereditary deafness and acquired deafness. According to the statistics, hereditary deafness accounts for 50% of all deafness patients. However, because the mode of inheritance is complicated, some of them show vertical transmission and some show horizontal transmission; some of them are continuous and some of them are intergenerational; some parents have normal hearing but their children have hearing impairment, and some parents are deaf but their children have normal hearing, so it is often difficult to determine hereditary deafness accurately, and sometimes it is hidden by other symptoms. This is where family history tracing becomes very important. Deafness due to genetic factors can be due to structural abnormalities of the auditory organs such as auricular malformations and atresia of the external auditory canal, or functional abnormalities, both conductive and sensory-neural deafness. Some children with deafness also have abnormalities in other body systems, creating a characteristic clinical syndrome. In white-frontal hair syndrome, the basic features are white-frontal hair, translucent blue coloration of both eyes or one eye i.e. iris heterochromia, and areas of skin that lack pigmentation are visible. Trisomy, also known as congenital deafness, is characterized by peculiar facial and intellectual developmental disorders, wide eye spacing, small eye fissures, low nasal bridge and small external ears, and a smaller than normal head circumference. In some cases, the hearing is normal after birth, but only at a certain age do the deafness characteristics appear. For example, familial progressive sensorineural deafness, an autosomal dominant disorder, is a condition in which the child is born with no hearing impairment and only begins to show symptoms around age 10 and gets worse each year. Current deafness genetic testing technology helps in the diagnosis of this type of deafness. 2. Acquired deafness Acquired deafness is mainly due to diseases, drug toxicity and other environmental factors that cause deafness. Viral infectious diseases: Infection of the mother with certain pathogenic microorganisms during pregnancy, such as rubella virus, measles virus, herpes simplex virus, herpes zoster virus, cytomegalovirus, H. influenzae, and syphilis spirochetes can lead to abnormal development of the fetal auditory organs. Among them, the most aggressive is rubella virus. According to some people, if the mother is infected with rubella during the first trimester of pregnancy, the probability of deafness in the newborn can reach 60%. Although the incidence of infectious deafness has decreased significantly in recent years with the improvement of medical conditions. However, this type of deafness is usually severe and difficult to treat, and should still be taken seriously. Common infectious diseases that can cause serious hearing damage include: influenza, typhoid, scarlet fever, mumps, viral hepatitis, viral pneumonia, polio, etc. During pregnancy, fetal hearing impairment may also be caused by diabetes, chronic nephritis, hypertension, severe anemia, hypothyroidism, carbon monoxide poisoning, alcoholism, as well as major trauma and severe malnutrition. In the case of severe asphyxia and insufficient oxygen supply to the newborn, the hearing organs are the first to be affected, so the details of birth such as the length of labor, the use of oxytocic drugs, the presence of meconium in the amniotic fluid, the presence of the umbilical cord around the neck after birth, the presence of bruised skin, and how long it takes to cry should be fully noted. Uneventful births, forced use of induction devices, cranial trauma such as fetal head aspirators and forceps, or too rough a manual induction of labor can also damage the auditory organs or auditory centers and lead to deafness. Newborns born at less than 37 weeks of gestation are called preterm babies. If the birth weight is less than 2,500 g, the baby is called low birth weight. A lot of clinical data prove that premature babies and low birth weight babies are more likely to have hearing impairment and should be given full attention. Normal newborns begin to show jaundice 2 to 3 days after birth, which subsides after 10 to 14 days and is called physiological jaundice. If jaundice appears too early or subsides too late it becomes pathological jaundice, which is caused by a high concentration of bilirubin in the blood. This pathological state, if not corrected in time, can result in neurological damage, such as involvement of the auditory nerve, which can lead to sensorineural deafness. Age-related deafness is a phenomenon due to the gradual decrease of hearing ability with age. It is mainly characterized by high frequency hearing loss. In the early stages of senile deafness, it is possible to talk to people with whom you are familiar, but it is difficult to talk to people with whom you are not familiar. In the later stage, it is difficult to talk to everyone, but it is difficult to hear what the other person is saying, especially in a noisy environment, and it is difficult to answer the phone or watch TV. Age-related deafness is actually a degenerative change of the auditory system, and a reasonable hearing aid fitting is very helpful for age-related deafness. In recent years, some new ototoxic drugs have been introduced one after another and their ototoxic hazards have been underestimated, making the incidence of drug-induced deafness on the rise, which should be highly valued by the relevant authorities. At present, the following types of ototoxic drugs are still in clinical use: aminoglycoside antibiotics such as streptomycin, gentamicin, kanamycin, xinomycin, neomycin, tobramycin and jessamine. Non-aminoglycoside antibiotics such as chloramphenicol, viomycin, erythromycin, vancomycin, etc. Salicylates such as aspirin, finasteride, pautazone, etc. Diuretics such as tachyphylaxis, diuretic acid, gonzalib, etc. Antineoplastic drugs and herbal medicines such as aconitine, heavy metal salts (gong, lead, arsenic, etc.). The above drugs should be avoided as much as possible, and when they must be used, make sure to carefully inquire about family history before use to exclude family specificity; when using them, strictly control the dosage and method, pay close attention to adverse reactions and measure hearing regularly during use, and once tinnitus, deafness, and facial ankylosis appear, the drug should be stopped immediately and appropriate treatment measures should be taken. Deafness caused by noise and shock is noise deafness. The sudden appearance of high-intensity explosive sound and long-term exposure to the noise environment can cause damage to the inner ear hair cells, resulting in temporary or permanent hearing loss. Therefore, the management of industrial noise pollution, Walkman, MP3 sound too loud can also damage hearing should be concerned. The results of the second national sample survey of people with disabilities show that the main causes of hearing disability between 0 and 6 years old, in addition to unknown causes, are genetics, maternal viral infection during pregnancy, neonatal asphyxia, drug deafness, premature birth and low birth weight babies; the main causes of disability in the group of 60 years old and above, in order, are senile deafness, otitis media, systemic diseases, noise and shock and drug deafness; rural and urban causes of disability In comparison, the causes of hearing disability in rural areas were higher than those in urban areas, including unexplained deafness, otitis media, hereditary deafness, infectious diseases, maternal and maternal viral infections, and neonatal asphyxia. Therefore, it is very important to develop prevention strategies for the main factors that cause hearing defects at birth such as genetic and maternal-pregnancy infections, and hearing disability such as otitis media, noise pollution, ototoxic drugs, and old age.