Objectives: To determine the long-term change in static admittance values of subjects with a positive or negative history of otitis media (OM) and ventilation tube (VT) insertion; and to investigate the association between static admittance values and tympanic membrane abnormalities.
Design: Prospective follow-up study.
Subjects: A total of 358 subjects with or without a history of OM (OM+ or OM-) and VT insertion (VT+ or VT-) derived from a birth cohort that had been observed from preschool to adulthood.
Main outcome measures: Otomicroscopic and tympanometric data obtained at subject ages 8 and 18 years.
Results: Static admittance values generally increased with age. At age 8 years, static admittance values were highest in OM+VT+ ears and lowest in OM- ears. At age 18 years, the difference between OM+VT+ and OM+VT- ears was larger, while the difference in static admittance values between OM+VT- and OM- ears had disappeared. In the group of VT+ subjects, the proportion of extreme static admittance values increased from 16% to 35% between ages 8 and 18 years. Correlation coefficients of individual static admittance values at 8 and 18 years were high in all groups and ranged from 0.61 to 0.85. We could not demonstrate an intermediate role of tympanic membrane abnormalities in the relation between VTs and static admittance at young adult age, except for atrophy.
Conclusions: The static admittance value at age 8 years was a strong predictor for the value at age 18 years. A VT+ status was associated with a larger increase in static admittance than can be explained on the basis of age alone.