According to Chinese national standards, hearing loss can be divided into the following categories: (decibels, i.e. dB) Normal hearing: -10 to 25 decibels Clear analysis of general sounds and speech. Mild hearing loss: 26～40 decibels It is difficult to distinguish small sounds, such as the sound of wind blowing in the woods. Moderate hearing loss: 41 to 55 decibels Have difficulty hearing everyday speech, feel blurred when talking to people, begin to need the help of hearing aids. Moderate to severe hearing loss: 56 to 70 decibels. Hearing aids can be helpful for those who still feel blurred by the sound of cars. Severe hearing loss: 70-90 decibels or more, for shouting and loud sounds, such as car horns. Hearing aids are more helpful for those who can only respond to the sound of drums. Very severe hearing loss: greater than 90 decibels, usually extremely difficult to feel the presence of sound, need to rely on the assistance of hearing aids to feel the force of sound vibration. Hearing loss of moderate degree should be equipped with hearing aids. Suitable hearing aids not only help you hear better, but also stimulate the hearing nerve. So, who needs a cochlear implant for deaf patients? The selection criteria for adult patients are: The patient is 18 years of age or older. Patients with bilateral severe or profound sensorineural deafness and postlingual deafness. The patient is unable to hear even with the best hearing aids in both ears. On imaging, the patient’s cochlea was not contraindicated to the implanted electrode sequence and the mastoid was not contraindicated to the implanted receiving stimulator. On medical examination, the patient had no contraindications to general anesthetic surgery and postoperative training. The patient should have a positive result for the electrical stimulation test of the tympanic capsule. The patient should be psychologically and emotionally suitable for cochlear implantation. Selection criteria for pediatric patients: The child should be deaf in both ears and be at least 18 months of age. The child is unable to receive help or receives minimal help even with the best hearing aid for both ears. The open speech discrimination score was 0% and the closed speech discrimination score was 0%. On imaging, the patient’s cochlea was not contraindicated to the implanted electrode sequence and the mastoid was not contraindicated to the implantation of a receive-to-stimulator. On medical examination, the patient had no contraindications to general anesthesia surgery and post-training. The family and the child had realistic expectations of the postoperative outcome and were willing to participate in the rehabilitation training. The child will use spoken language as the primary mode of communication and receive an auditory/speech or auditory/speech-based educational program. The child’s parents also agree to the program. If possible, an electrical stimulation test of the headphones may be performed in older children and should be positive. Hearing threshold response with hearing aids can also be tested to determine the function of the auditory nerve.