\s=b\Charts of 161 patients with unilateral chronic otitis media were reviewed for evidence of sensorineural hearing loss, defined as the difference in preoperative bone conduction thresholds between diseased and normal contralateral ears. Mean bone conduction differences were small but statistically significant, ranging from 5.6 to 12.8 dB across the frequencies. Approximately 45% of the subjects had differences greater than 10 dB for high frequencies, but less than 12% had a difference greater than 20 dB for the pure-tone average. Significant relationships were found between sensorineural hearing loss and the presence of acquired cholesteatoma in the middle ear, diseased mucosa of the promontory and hypotympanum, and diseased ossicles. These findings suggest that more severe middle ear disease may result in sensorineural hearing loss. However, for the majority of subjects, the amount of sensorineural hearing loss was judged not to be clinically significant.(Arch Otolarygol Head Neck Surg. 1989;115:814-816) Chronic otitis media (COM) is asso¬ ciated with various sequelae, including a mixed hearing loss. The conductive component of this hearing loss is acknowledged. Several investi¬ gators have collected data in support of a significant sensorineural compo¬ nent with both experimental animals and clinical studies.18 These investiga¬ tors have emphasized the necessity for prompt clinical action in light of the possibility of sensorineural hear¬ ing loss (SNHL).Other investigators, although find¬ ing evidence of SNHL in patients with COM, have questioned the clinical sig¬ nificance of the degree of hearing loss.9 The clinical impression of two of us (C.S. and J.L.S.) has also been that significant SNHL as a result of COM is not typical. Few studies have direct¬ ly compared the amount of SNHL in COM and control ears. Most studies have compared the percentage of patients meeting specified criteria for SNHL, but have not reported the actual difference in amount of hear¬ ing loss between the diseased and control ears. Those studies that have, report only small average differ¬ ences.9This retrospective study quantified the amount of relative SNHL by com¬ paring COM ears with the normal contralateral ears in patients with unilateral COM, using a matchedpairs approach. In addition, we exam¬ ined the relationship between this rel¬ ative amount of SNHL and other important patient characteristics that reflect the extent of disease. SUBJECTS AND METHODS SubjectsThe subjects included those patients of the Otologie Medical Group, Los Angeles, Calif, who were diagnosed with unilateral COM and who ultimately underwent sur¬ gery. The normal contralateral ear served as the control. The diagnosis of COM was based on a physical examination showing a tympanic membrane perforation, choles¬ teatoma, or ossicular destruction. Subjects were excluded for the following reasons: prior otologie surgery; bilateral disease; history of head trauma; posttraumatic tympanic membrane perforation; labyrin¬ thine fistula; congenital cholesteatoma...