The negative on/off effect in cochlear and early stapedial otosclerosis.

Acoustic reflex patterns were reviewed for 100 patients suspected of having cochlear otosclerosis (group 1) and 73 patients with confirmed stapedial otosclerosis and conductive hearing losses of less than 5 years duration (group 2). Three abnormal reflex patterns were exhibited by these patients--"negative on/off," "no response when the probe was in the affected ear," and "no response when the stimulus was in affected ear." Results showed that the negative on/off pattern was equally as common for the two subject groups. The "no response" patterns were more common for the early stapedial otosclerosis group. The presence of acoustic reflex patterns classically associated with stapedial otosclerosis in patients with cochlear otosclerosis leads us to predict that some degree of stapedial fixation is common in many cases of cochlear otosclerosis. Based upon these findings, the presence of the negative on/off pattern in patients with mild sensorineural hearing loss, excellent speech discrimination, and a family history of hearing loss, is now considered indicative of cochlear otosclerosis.