Cochlear implant composition and working principle The cochlear implant, also known as the electronic cochlea, is an electronic device that replaces the function of the human ear by converting the sound in the environment into an electrical signal and transmitting the electrical signal to the patient’s cochlea, stimulating the residual auditory nerve of the cochlea and producing hearing from the surface. It consists of two parts, namely the in vivo implant part and the in vitro part. The extracorporeal device consists of a speech processor, a directional microphone and a transmission device. The sound is received by the microphone and converted into an electrical signal and transmitted to the speech processor, which converts the electrical signal into a digital signal that is transmitted by the transmitter to the in vivo receiver. The in-vivo value entry component consists of a receiver/stimulator and an electrode set implanted in the cochlea. The electrical signal is transmitted to the electrodes, through which the electrical signal is transmitted to the auditory nerve. The auditory nerve transmits the sound signal to the brain, producing the sense of hearing. A child is the hope of a family. From the time a healthy and lively baby is born to the time he or she cries out “Dad” and “Mom” clearly, these two simple words carry the happiness of many families. However, when the child grows up, but does not respond to external sounds, can not speak, for the whole family is a heavy blow. As the saying goes, “nine out of ten deaf children are dumb”, and children living in a silent world cannot learn to speak. Now, a high-tech alternative, the cochlear implant, allows us to fight against nature: cochlear implantation, to rebuild the hope of hearing! Cochlear implantation is an option for those who have severe or profound hearing loss in both ears, where hearing aids are ineffective and the lesion is diagnosed in the cochlea. This includes patients who are prelingually deaf and postlingually deaf. 1. Patients with prelingual deafness: 1. Severe or profound sensorineural hearing loss in both ears. 2. 1 to 17 years old, with the best age being 1 to 5 years old. 3. No significant improvement in hearing ability after wearing hearing aids. 4. No contraindication to surgery. 5. Families have a correct understanding of cochlear implants and appropriate expectations. The selection criteria for patients with postlingual deafness: 1. Severe or very severe sensorineural hearing loss in both ears. 2. Patients of all ages with post-speech deafness, with adult post-speech deafness being one of the best indications. 3. No significant improvement in speech recognition ability after hearing aid fitting. 4. No contraindication to surgery. 5. The patient and family have a correct understanding of cochlear implants and appropriate expectations.