Cochlear otosclerosis: acoustic reflex findings.

Progressive cochlear impairment develops in a small percentage of patients with clinical otosclerosis, apparently owing to involvement of the cochlea by the otosclerotic bone. In recent years it has been postulated that otosclerosis frequently produces a pure sensorineural hearing impairment without stapedial involvement. We investigated the acoustic reflex responses in a group of patients diagnosed as sensorineural otosclerosis and compared these reflex findings with the findings in patients with confirmed otosclerosis but with a minimal conductive impairment. In the minimal conductive hearing impairment group we substantiated the findings of others that the negative on-off reflex is common in otosclerotic patients whose conductive impairment is 10dB or less. In the group with cochlear otosclerosis we found abnormal reflexes in 58 percent of the patients. These findings indicate that stapedial involvement is common in patients thought to have pure sensorineural otosclerosis.