The severity of hearing damage depends on the level of sound that can be heard, and the degree of hearing loss is assessed by brainstem audiometry. Hearing loss is usually classified into five grades, normal, mild, moderate, severe and very severe, and the degree of hearing loss is divided into the following categories: 1. Normal hearing is -10 decibels to 25 decibels, and 25 decibels is a clear analysis of general sounds and and speech; 2. Mild hearing loss is 26-40 decibels, and it is difficult to recognize very small sounds, such as the sounds of the woods and the wind blowing; 3. Moderate hearing loss is 41-55 decibels, and it is difficult to hear everyday speech. Mild hearing loss is 26-40 decibels, it is difficult to recognize very small sounds, such as the woods, the sound of the wind blowing; 3, moderate hearing loss is 41-55 decibels, there are auditory difficulties in everyday language, talking to people feel fuzzy, and begin to need to use the help of hearing aids; 4, moderate and severe hearing loss is 56-70 decibels, for the larger sounds of the conversation, the sound of the horn of the car is still feeling fuzzy, the help of hearing aids is greater; 5, Severe hearing loss is 70-90 decibels, for shouting and loud sounds, such as car horns, drums to have a response, hearing aids help very much; 6, very severe hearing loss is greater than 90 decibels, usually very difficult to feel the presence of sound, need to rely on the aid of hearing aids to feel the vibration of the sound force.