Objective: To assess the time needed to perform tympanometry, the success rate and the importance of the child's cooperation for the accuracy of minitympanometry in detecting middle ear fluid, and the relation between the static admittance of the tympanogram and the weight of the middle ear fluid.
Study design: Two series of patients were enrolled. The first consisted of 206 consecutive children (mean age 4.7 years, range 1 month to 16 years) from the Outpatient Emergency Department of Pediatrics in the University of Oulu; the second group consisted of 162 children (age range 7 months to 8 years) who were referred to the Department of Otolaryngology for adenoidectomy, tympanostomy, or both procedures. In the first series the success rate and the time needed to complete a minitympanometric examination on each ear were recorded. In the second series, the tympanograms were evaluated according to the cooperation of the children at the time of the tympanometric examination, and the weight of the middle ear fluid was measured and compared with the static admittance of the minitympanometric curve. Sensitivity and specificity values were calculated separately for cooperative and uncooperative patients.
Results: In the first series, the mean time needed for tympanometry was 2.1 minutes (range 0.5 to 10 minutes), and 179 (86.9%) of the patients were cooperative. In the second series, the sensitivity and specificity calculated for tympanometry in detecting middle ear fluid were 79% and 93% among the cooperative children. In the uncooperative group, sensitivity and specificity were 71% and 38%, respectively. The weight of the middle ear fluid varied from 5 mg to 695 mg. There was a significant negative correlation (r = -0.66, p < 0.001) between the static admittance in minitympanometry and the weight of the middle ear fluid.
Conclusion: Minitympanometry can be done quickly, it fails rarely, and in cooperative patients it is a better tool than has been earlier suggested, but it is useless in uncooperative children. The amount of middle ear fluid varies notably even among young children.