Otoacoustic emissions in young adults with a history of otitis media.

The aim of this study was to investigate otoacoustic emissions in young adults who had a history of otitis media (OM) in childhood and to assess whether a history of OM had an irreversible effect on hearing. We studied 116 cases between 15 and 25 years of age, divided into three groups. Each subject underwent a single examination comprising otoscopy, pure-tone audiometry (PTA), tympanometry, and transient evoked otoacoustic emission (TEOAE) and distortion product otoacoustic emission (DPOAE) testing. Subjects in the first and second groups had normal audiometric hearing thresholds and type A tympanograms. The only difference between the first and second group was the presence or absence of a history of OM. The third group consisted of patients diagnosed as having active OM; these patients had poorer hearing thresholds and type B or C tympanograms. After statistical analysis of TEOAE and DPOAE results (one-way analysis of variance test), significant differences were noted between groups. Otoacoustic emission levels were, unsurprisingly, lowest in the third group, as expected. However, the most striking result in the study was that significantly fewer otoacoustic emissions were detected in subjects with a history of OM than in subjects without a history of OM. These findings suggest that OM in childhood may cause minor but irreversible damage to the middle ear or cochlea. Otoacoustic emissions testing can be used to detect this sub-clinical damage.