Hypothesis: This study investigated whether otoacoustic emissions (OAEs) in patients with Ménière's disease show abnormal properties.
Background: Patients with Ménière's disease experience vertigo, tinnitus, and hearing loss. OAEs are sounds generated in the inner ear, and their presence is associated with normal hearing.
Methods: Click-evoked OAEs and distortion product OAEs were measured in 100 patients with Ménière's disease.
Results: The incidence of the emissions in affected ears (56%) was lower than in unaffected (i.e., contralateral) ears (85%). The mean emission amplitude in affected ears was also significantly lower (2.6 dB), and the mean amplitude in unaffected ears was lower than in normal-hearing ears (5.3 dB). These differences were likely caused by the hearing loss involved. Further, ears with OAEs clearly showed smaller hearing losses than ears without OAEs (24-dB difference). The average hearing loss showed correlations with the emission amplitudes, although this correlation was not very strong; when plotted against the smallest hearing loss, a certain upper boundary for the emission amplitude was present. Also, the amplitude of click-evoked OAEs showed a considerable correlation with the largest of the three distortion product OAEs.
Conclusion: OAEs in patients with Ménière's disease differed from those in normal-hearing ears but did not differ from those in non-Ménière's ears with equivalent hearing loss. This was best observed by comparing emission amplitude with smallest hearing loss instead of mean hearing loss.