Effect of middle ear effusion on distortion product otoacoustic emission

It is well documented that children, particularly between the ages of about 2 and 6 years, exhibit a high prevalence and incidence of otitis media. Distortion product otoacoustic emissions (DPOAEs) offer great potential for clinical testing of cochlear function in children. The aim of the present study was to determine the influence of middle ear effusion and physical properties of the effusion on the recording of DPOAE.

Nineteen children (38 ears) undergoing myringotomy and/or tympanostomy tube insertion for secretory otitis media were studied. Pre-operative and post-operative first day DPOAE signal to noise ratios were compared. The results were analyzed by paired samples test and ANOVA statistical methods.

We were found significant differences between pre-operative and post-operative first day DPOAE signal to noise at 1, 1.5, 2 and 4kHz. In addition, comparison of the pre-operative DPOAE signal to noise ratio and per-operative middle ear findings are shown significant differences between glue (thick mucous) and the other three groups (mucous, serous and no-effusion groups) at 2 and 4kHz, and between glue and no effusion group at 8kHz. Also post-operative DPOAE signal to noise ratio in relation to per-operative middle ear findings were significantly different at 2, 4 and 8kHz. The most increase of emissions at the post-operative first day was seen in ears with glue effusion at 1 and 2kHz.

Otitis media with effusion can be monitored by DPOAE measurement pre-operatively and post-operatively. In the pre-operative evaluation, glue effusion may cause a reduction in the emissions at 2, 4 and 8kHz more than the other kind effusions.