The human body is continuously exposed to the noise environment, after a long time, will appear on the hearing caused by temporary hearing threshold shift, hearing dull, but this situation does not last long, as long as the noise place to leave the quiet place to stay for a period of time, hearing will gradually restore the original state, this phenomenon is called temporary hearing threshold shift, also known as auditory fatigue. Hearing fatigue is due to noise endangering people’s hearing, the light is high-frequency hearing threshold damage, in the middle is deaf, the heavy is the ear drum rupture. Generally, it is manifested as a reduction in the perception of stimulating sounds and sounds of similar frequencies, but this reduction is generally temporary, and the perception of the auditory organ returns to normal not long after the stimulating sound stops acting. The degree of noise damage to human hearing is closely related to the form, intensity, frequency and exposure time of the noise. Differential diagnosis: 1, hearing loss: normal hearing is a category of auditory sensitivity, which is the average of normal ear audiometry of healthy young people, not an absolute value. When there is a lesion or functional damage to the sound-transmitting or sound-sensitive part of the auditory system, it produces a hearing impairment, usually called hypoacusis. The degree of hearing loss can vary from mild to severe, from hard of hearing in the mild case to deafness in the severe case. What is generally referred to as deafness is a near total loss of practical hearing. Children who have lost their hearing since childhood and have lost the opportunity to learn language become deaf. 2.Hearing deficiency: moderate deafness means hearing level drops to 40-70 decibels, severe deafness means hearing level drops to 70-90 decibels, and profound deafness means hearing level drops more than 90 decibels. Of course, regardless of the degree of deafness, medical testing and medical treatment are required. Observing hearing defects in very young babies is not an easy task. Despite hearing deficits, babies can smile, stir, and respond to sounds. Because the sound is accompanied by a stream of air that the baby feels and turns his head, it is difficult for parents to detect the hearing deficit. Because of this, it is essential and important to have your baby’s hearing checked regularly after birth. Conductive deafness is related to the outer and middle ear. The main cause of disability is a severe chronic otitis caused by recurrent severe otitis. The main characteristic of conduction deafness is that the hearing loss is usually mild to moderate. It must therefore be treated as soon as possible. The statistics are alarming:1/3 of babies suffer from this ear disease during a period of two consecutive months before the age of 3. However, we do not yet have figures on how many babies develop conductive deafness. The disease can be cured with antibiotics and tympanic cannulae. However, if these methods do not improve your baby’s hearing, then he may have sensory deafness that is just not detected. 3.Hearing impairment: Hearing impairment refers to congenital or acquired causes that lead to structural defects of the auditory organs or partial or total functional impairment, resulting in difficulty in hearing or recognizing sound; the identification criteria are as follows: (1) After receiving a conscious pure tone hearing examination, the euphonic frequency hearing is more than 25 decibels. (2) If the patient is unable to undergo the pure tone hearing examination in the preceding paragraph, the patient will be identified by means of other hearing examination. The diagnosis can be made based on the patient’s long-term noise environment and hearing condition.