Screening tympanometry during the first year of life.

150 healthy children were regularly investigated with tympanometry during the first year of life. Normal middle ear pressure was found in nearly all children at birth. At the age of 6 months, 62% of the ears had a pressure of 0-99 mmH2O. In 37% the pressure was between -100 and -350 mmH2O and 1% had flat curves. At the age of 9 months, the tympanograms further deteriorated and at 12 months, only 40% of the ears had a pressure of 0 to -99 mmH2O, 28% had a pressure of -100 to -199 mmH2O, 19% a pressure of -200 to -350 mmH2O and 13% had flat curves, indicating secretory otitis. At 1 year, the tympanograms were worse than in any other age group investigated so far. The dominant cause of the reduced middle ear ventilation was catarrhalia, the frequency of which increased during the period from 6 to 12 months.