Patients who have a hearing loss can go to the hospital for a hearing test, usually in a soundproof room, follow the doctor’s instructions, if you hear a sound in your hand, press the button, so that you can indicate that you hear clearly, the doctor will give sound stimulation according to different frequencies for the patient to respond. If there is a response, the doctor can mark the corresponding decibel to indicate the patient’s hearing. Pure tone audiometry is a subjective audiometric test, which has a certain degree of error. If the patient does not cooperate well or if there is pseudo-deafness, an objective audiometric test called brainstem evoked potential can be considered, which can reflect the hearing of the patient’s ears in a relatively realistic way.