”Otoacoustic emission is the product of the energy-consuming active activity of the human cochlea, which is transmitted outward through the auditory chain and the tympanic membrane, releasing a form of sound energy into the human external ear canal. It is the reverse process of sound vibrations passing through the tympanic membrane and the auditory chain into the inner ear. The “otoacoustic emission” originates in the cochlea in the form of mechanical vibrations, and the vibrational energy originates in the outer hair cells, whose activity, through various pathways, causes some form of vibration in the basilar membrane, and these vibrations are transmitted in the lymphatic fluid of the inner ear in the form of pressure changes, which vibrate the auditory chain and tympanic membrane through the oval window, and eventually cause air vibrations in the external auditory canal. The final result is the vibration of the air in the external ear canal. Indications for Otoacoustic Emission Testing It is currently believed that the hearing loss, poor discrimination and “resonance phenomenon” of clinical sensory nerve deafness are most likely the result of an impaired active mechanism of the outer hair cells. The “otoacoustic emission” is like an “acoustic probe”, which provides a direct clinical window into the mechanical activity of the cochlea, especially the outer hair cells. It is important for the localization and qualitative diagnosis of deafness lesions, for understanding the characteristics of the lesions, and for guiding treatment and prevention. The otoacoustic emission detection system is mainly used in the following areas: 1. Hearing screening in children, especially in newborns, a few days after birth, can be performed, and is of great value in detecting early hearing impairment. 2.The occurrence and development of drug-induced deafness, noise-induced deafness and deafness in the elderly can be dynamically observed. 3.The judgment of the functional status of the efferent nerve. The degree of deafness is generally classified as follows: <5db< font=""> as normal; 25-40dB as mild deafness (difficulty in hearing faint sounds); 40-55dB as moderate deafness (difficulty in hearing ordinary dialects); 55-70dB In recent years, hearing screening for newborns has become a routine method for the differential diagnosis of hearing impairment in infants and children. Newborns and children at risk for hearing impairment should undergo further comprehensive audiological evaluation to achieve timely diagnosis and early intervention. The clinical validation of newborn hearing screening and nursing interventions has shown that the use of scientific methods such as otoacoustic emission testing to monitor and evaluate infants’ audiology on a regular basis and the adoption of corresponding interventions can effectively complement the smooth conduct of infant hearing assessment and improve the compliance of infants’ hearing follow-up.