Otoacoustic emission measurements in evaluation of the immediate effect of ventilation tube insertion in children.

It is generally acknowledged that hearing assessment is needed before and after possible surgical intervention in children with otitis media with effusion. The conventional method in young children is visual reinforcement audiometry, which requires much time and cooperation from the child. The assessment of otoacoustic emissions may be an alternative, as it is proven to be rapid, easy, and objective as a screening procedure. We studied the applicability of click-evoked otoacoustic emissions to assess hearing acuity in children with otitis media with effusion who were scheduled for ventilation tube insertion. To avoid cooperation problems, the measurements were performed in the operating room immediately before and after ventilation tube insertion with the child under general anesthesia. None of the ears tested (n = 29) showed any increase in otoacoustic emissions when preoperative and postoperative levels were compared. At follow-up visits, however, 80% of the tested ears did. The acute outcome may be best explained by assuming that the surgical manipulations themselves were responsible, either through their fatiguing effects on the outer hair cells caused by the suctioning noise, or through their mechanical effects on the middle ear processes that govern reverse transmission from the cochlea to the outer ear canal. We conclude that it is not worthwhile to measure otoacoustic emissions directly after ventilation tube insertion to assess the effect on hearing acuity, although they may be valuable in the outpatient setting.