A. History taking The etiology and pathogenesis of deafness: The patient’s hearing history, history of tinnitus and vertigo, history of ototoxic drug exposure, history of noise exposure, history of systemic acute and chronic infections, past history of otology, developmental factors (systemic or local developmental abnormalities, intellectual development, etc.), family history of deafness, history of hearing aid wear and other causes, such as epilepsy, mental conditions, etc. should be understood. Children with deafness should also include: maternal pregnancy history, pediatric birth history, pediatric growth history, speech development history, etc. Language ability (e.g., articulation characteristics, clarity of sound composition) and language comprehension and communication ability (e.g., oral, lip reading, sign language, written, guessing, etc.). Otological examination including auricle, external auditory canal, tympanic membrane and eustachian tube, etc. Audiological examination 1. Subjective hearing threshold determination: children under 6 years old can use pediatric behavioral audiometry, including behavioral observation audiometry, visual reinforcement audiometry and play audiometry; 2. Acoustic conductance measurement: including tympanic chamber pressure curve and stapedius muscle reflex; 3. Auditory brainstem response (ABR), 40Hz correlation potential (or multi-frequency steady-state evoked potential); 4. Otoacoustic emission (transient evoked otoacoustic emission or 5.Speech audiometry: speech hearing threshold test is language perception threshold and language recognition threshold; speech recognition test includes speech test word list and pediatric speech test word list; 6.Hearing aid matching: professional audiologists are required to match hearing aids, generally need to wear both ears, after matching, hearing threshold test and speech recognition test should be done, and then auditory language training for 3-6 months; 7.Vestibular function 8.Electrical stimulation test of drum head: the test includes threshold, dynamic range, frequency discrimination, interval discrimination and temporal discrimination and other psychophysical examinations. Imaging is the most important test for patient selection. A thin layer CT scan of the temporal bone, three-dimensional reconstruction of the cochlea, and MRI of the internal auditory tract should be routinely performed, and cranial MRI should be performed if necessary. For patients with certain language experience or ability, speech ability assessment (language structure and function) should be done, including speech intelligibility, vocabulary, comprehension, grammar, expression and communication ability; for uncooperative children younger than 3 years old, the “parent-child game” video observation method should be used for evaluation, For children younger than 3 years of age who were uncooperative, a “parent-child play” video was used to evaluate the patients’ language ability at this stage. Psychological, intellectual and learning ability assessment For children over 3 years old who lacked language ability, the Schneider Learning Ability Test was used, and for those under 3 years old, the Greifers Mental Developmental Behavior Inventory was used. For children with suspected mental retardation (IQ < 68< span=""> on the Schneider Learning Ability Assessment and mental developmental quotient < 70< span=""> on the Greiffels Test) or abnormal psychological behavior, patients should be advised to go to an authoritative institution for further observation, diagnosis, and evaluation. For patients with socio-cultural mental retardation, cochlear implantation may be considered; however, for patients with non-socio-cultural mental retardation, ADHD, autism, or other mental retardation, parents should be informed of the great difficulties that these disorders may bring to the post-operative rehabilitation of the patient, and parents should be helped to establish objective psychological expectations. Pediatrics or internal medicine evaluation General physical examination and related auxiliary examinations should be performed. Family conditions and rehabilitation conditions Families who have received professional training or have regular guidance from a language training teacher can provide auditory language training for the child at home; otherwise, the child should be sent to a rehabilitation school or institution for deaf children.