Sudden deafness refers to sudden, transient, severe and sound-perceiving deafness. The patient in most cases can accurately supply the time, place and situation of the onset for the doctor. The disease is also called idiopathic Sudden deafness and idiopathic fulminant deafness. It preVails in the middle-aged people, and the average age is 46, without obvious difference in sex.At present, it is believed that the onset of disease is related to the dysfunction of otic blood supply or viral infection. The rupture of window membrane (round window membrane) and vestibular membrane was believed to be one of the cause of the disease. Presently, perilymphatic fistula due to rupture of window membrane is considered as an independent disease.