The preoperative evaluation of a cochlear implant patient is very important and is the inevitable process by which the physician determines whether a deaf patient is suitable for cochlear implant intervention. To be eligible for cochlear implantation, the surgeon must first know the degree and nature of the deafness, whether the deafness has a specific cause, and the patient’s general condition. Can the patient tolerate anesthesia and the surgical procedure? Are there any contraindications to surgery? Are there any other concomitant diseases that may affect the recovery outcome after cochlear implantation? The preoperative evaluation of cochlear implantation is very complex and extensive, so we will discuss each of the major items below. First of all, cochlear implantation is a method of auditory intervention for patients with severe sensorineural deafness, so the first thing is to conduct an audiological evaluation to understand the degree and nature of deafness and the impact on speech and language skills. . For children who cannot cooperate with pure tone audiometry, behavioral observation, visual reinforcement and play audiometry can be used. Objective hearing test 1. Acoustic conductance (tympanogram and acoustic reflex): To understand the functional status of the middle ear. Patients who are suitable for cochlear implantation should have a type A or C tympanogram, which indicates that the middle ear function is normal or basically normal. If it is a type B, then otitis media may exist, and generally, otitis media should be treated before cochlear implantation. Patients with cochlear implants should be unresponsive to acoustic reflexes because of the severe degree of deafness. 2. Auditory brainstem evoked potentials (ABR): For younger children who cannot cooperate with primary auditory observation, short-acoustic ABR is the main method to understand their degree of deafness. In addition, ABR combined with other tests can also help the physician to detect specific deafness and give some indication of the prognosis for cochlear implantation. 3. Otoacoustic emission (OAE): It mainly understands the functional status of the inner ear. Those who are suitable for cochlear implantation should have inner ear pathology; therefore, DPOAE or TEOAE cannot be elicited bilaterally for conventional cochlear implantation. 4. Multi-frequency steady-state evoked potentials (ASSR):To help understand the residual hearing of implant candidates, response thresholds in the 0.5kHz, 1kHz, 2kHz, and 4kHz speech frequency ranges are generally tested. This is a suprathreshold function test for pediatric patients with hearing aids to find out how well they can hear in the preoperative intervention state. 1. Lin’s six tones perception test: Lin’s six tones basically cover the normal speech frequency range, through this test, we can roughly know the speech frequency loss of the child after the hearing aid, and provide the basic information for the doctor to judge whether the implantation surgery is needed. 2. Auditory behavior grading questionnaire (CAP): CAP is a grading standard for assessing auditory perception, suitable for children of any age, especially for children between 0 and 6 years old, and reflects the child’s level of hearing in daily life. If the hearing aid is not effective, implantation surgery can be considered. The Auditory Integration Questionnaire (MAIS, IT-MAIS) is used to assess the spontaneous responses of deaf children to sounds in daily life. The questionnaire covers three main aspects of hearing: acceptance of hearing devices, perception of sound, and understanding of the meaning of sound. A score of <20 on the Auditory Integration Questionnaire indicates that the original intervention was ineffective and that cochlear implantation may be considered. < p=""> 4. Auditory-Speech Ability Test 1. Speech Recognition Rate Test (sometimes with the addition of Phrase Recognition Rate Test): Tests the ability of deaf patients to acquire, recognize, and understand speech information. 2.Speech Intelligibility Test: To understand the development of the deaf patient’s own speech ability and the clarity of spoken language. 3. For children or younger deaf patients, the conventional speech test methods may be too difficult for them, so there is a special auditory-speech test for children ① Rhyme recognition, vowel recognition, and bisyllabic recognition: an average score of ≤70% in the three items is an auxiliary criterion to determine the need for cochlear implantation. ②Speech Intelligibility Rating Assessment Questionnaire (SIR):A questionnaire was used to assess speech intelligibility. Secondly, after the audiological examination meets the criteria for cochlear implantation, deaf patients also require imaging evaluation, including high-resolution temporal bone CT and auditory nerve MRI. CT shows whether the bilateral cochlea and internal auditory canal structures are normal. MRI of the auditory nerve can show fluid filling of the cochlea and internal auditory canal and abnormalities in the development of the auditory nerve. If necessary, a head MRI is added to understand any organic/progressive lesions in the brain. Again, certain psychiatric, intellectual, and behavioral assessments are needed to understand the mental development of the pediatric population and the presence of psychological disorders and behavioral abnormalities. Specifically, these include: i. Hie-Ne learning ability test scores Suitable for people aged 3-17 years old to test, generally requiring a score >84. ii. Greyfriars mental development test scores Suitable for people under 3 years old or who cannot cooperate in completing the Hie-Ne test, generally requiring a score >86. iii. Autism and autism tests 1. Kirschner Autism Behavior Scale scores: Suitable for subjects aged 2 years or older, requiring a score <10; < p= ""> 2. Rutter’s Child Behavior Questionnaire score: for subjects 7-16 years of age, a score of <9 is required.< p=""> All of the above examinations or tests are currently the main components of the preoperative evaluation required for cochlear implant candidates. Of course, as experience with cochlear implantation continues to accumulate and medical technology advances, the relevant tests may change somewhat depending on the actual clinical situation. Some special tests may also be added for those who are ready for implantation with special circumstances. Finally, the interpretation and comprehensive evaluation of the results of all examinations is the key to determining whether a deaf patient can ultimately undergo cochlear implant intervention. For this reason, cochlear implantation programs internationally are now multidisciplinary teams, especially in the form of a Multiple Disciplinary Team (MDT) for the preoperative evaluation of cochlear implants.