Objective: We examined relationships between tympanometric findings and the presence or absence of middle-ear effusion in a population-based sample of children under the age of 3 years.
Methods: In a study of children's development in relation to early-life otitis media, we enrolled 6350 infants soon after birth and evaluated them regularly for the presence of middle-ear effusion. In 3686 of the children, we compared tympanometric findings with otoscopic diagnoses. We categorized tympanograms according to varying combinations of tympanometric peak height, peak pressure, and width, and calculated for each resulting category the percentage of the associated ears diagnosed as having effusion. Using these findings we developed algorithms for estimating the probability of middle-ear effusion associated with tympanograms of any configuration.
Results: For tympanograms generally, the lower their height and the greater their width, the greater was the probability of associated middle-ear effusion; the probability also was greater when peak pressure was negative rather than positive. Among children > or = 6 months of age, effusion was diagnosed in only 2.7% of ears with tympanometric height > or = 0.6 mL, but in 80.2% of ears with flat tympanograms. Relationships among younger infants were similar but less consistent. In both age groups, the tympanographic configurations most commonly encountered were associated with either a relatively low probability (<30%) or a relatively high probability (>70%) of the presence of middle-ear effusion. The receiver operating characteristic curve we generated using the algorithm we developed for children > or = 6 months of age gave an area under the curve of 0.84. The algorithm performed equally well when applied to a separate group of children, suggesting that it is generalizable to other unselected populations.
Conclusions: The present report offers two alternative methods for estimating the probability of middle-ear effusion in children aged 6 through 35 months, given any combination of tympanometric values.