Normative values for tympanometry in 4-5-year-old children

The objective of this study was to determine normative values for tympanometric variables for 4-5-year-old children. Tympanometry was performed at a pre-scheduled visit at the age of 49-68 months on children recruited to a follow-up visit in a vaccine efficacy trial (n=756 children). Tympanograms obtained successfully from healthy ears were analysed. At the time of the visit, mean static acoustical admittance (SAA) was 0.52 cm3, mean tympanometric peak pressure (TPP) was -48 daPa, and mean tympanometric width (TW) was 101. Compared to results obtained for the same study population at 24 months of age, the SAA had increased significantly with age, while the values for TPP and TW had decreased with age. A history of previous tympanostomy tubes increased the admittance of the tympanic membrane by producing atrophic scars. Thus, the tympanograms obtained from ears with previous tubes were considerably higher and narrower (high SAA and low TW). In conclusion, this study further emphasizes the need for age-specific normative values for interpretation of SAA and TW.