①Conductive deafness: Impaired transmission of sound waves to the inner ear due to lesions in the outer and middle ear is called conductive deafness. (2) Sensorineural deafness: Deafness due to postcochlear lesions of the cochlea and auditory nerve or auditory center that cause cognitive dysfunction of sound sensation and perception. (③) Mixed deafness: both conduction deafness and sensorineural deafness are present, and both conduction deafness and sensorineural deafness are present, and pure tone audiometry shows a gap between bone and air conduction greater than 10db.