(2) The lesion of sensorineural deafness is located in the inner ear, auditory nerve or auditory conduction pathway. Such as inner ear hypoplasia, drug-induced deafness, noise deafness and acoustic neuroma.
(3) Mixed deafness: both conductive deafness and sensorineural deafness.
(4) Central deafness: It can occur anywhere in the central nervous system from his nucleus to the cerebral cortex.