Abstract
An epidemiological study of negative middle ear pressure in children made it possible to test its relationship to conductive hearing loss. About 350 children were subjected to a screening procedure recording audiogram and middle ear pressure five times during a 12-month period. Those children who failed to perceive just one tone or who had a middle ear pressure equal to or worse than -150 mmH2O in one or both ears were referred to the Hearing Clinic for conventional audiometry and middle ear pressure measurement each month. By computing the weighted average of the regressions for each child, a straight linear relationship was found between negative pressure and conductive hearing loss. In addition, a frequency dependence was found, the hearing loss being maximal at about 500 Hz. In general, the study shows that tympanometry is of limited value in predicting hearing loss in a child. The threshold for pathology of about -150 mmH2O, being a predisposing factor in secretory otitis media, corresponds to the upper confidence limit of the normal range of hearing loss found in this series. There is no distinct value of negative pressure that clearly distinguishes between normal and pathological condition, but it is concluded that a middle ear pressure worse than -150 mmH2O should be considered a probable hearing handicap.