The symmetry of paediatric tympanograms

Objectives.  The poorer outcome of myringoplasty in children in comparison with adults is commonly attributed to poor Eustachian tube function. The only routine test giving an indication of Eustachian tube function is tympanometry. It is common practice to look at the contralateral tympanogram as a predictor of the child's Eustachian tube function when deciding whether to proceed with myringoplasty. This relies on the assumption that Eustachian tube function is symmetrical. This study seeks to assess whether this assumption is correct.Method.  We collected copies of 297 pairs of tympanograms carried out in a paediatric ENT clinic over a ten‐month period. We compared the symmetry of tympanograms of children aged from 5 to 16 years.Results.  We looked at the association between normal Eustachian tube functions (type A) or abnormal Eustachian tube function (type B, C1 or C2) in one ear and Eustachian tube function in the other ear. A type‐A tympanogram in one ear predicted a type‐A tympanogram in the other ear with a sensitivity of 0.81 (95% CI 0.74–0.86) and specificity of 0.75 (0.66–0.82). The positive predictive value of a type‐A tympanogram was 0.82 (0.75–0.87) and the negative predictive value was 0.73 (0.65–0.81).Conclusions.  There is a good correlation of Eustachian tube function, as demonstrated by tympanometry, between the ears of a child. If Eustachian tube function does have an impact on myringoplasty outcome then the contralateral tympanogram should provide some help in the decision on timing of myringoplasty.