Impedance and tone screening of school children.

Impedance screening has supplemented tone screening on 5 886 seven-year-olds (11 772 ears) in five separate investigations carried out between 1972 and 1978. In the last and most conclusive study, 1 027 seven-year-olds were investigated with impedance and tone screening. Those children who failed had a repeat test at school after 4-6 weeks. Only those who failed the second screening test were referred for a final clinical control. At this investigation the otologist found 5.8% pathological ears. The stapedius reflex threshold testing (ipsilateral stimulation), criterion level greater than or equal to 110 dB SPL, rated 7.6% of the ears as abnormal. Tympanometry resulted in 6.4% pathological ears. Tone screening showed pathological values at 0.5 kHz in 1.9%, at 3.0 kHz in 1.5% and at 4.0 kHz in 2.1%. On the basis of our findings in the above-mentioned studies the following screening procedures are recommended: Tone screening at 0.5 and 4.0 kHz supplemented by tympanometry. A middle ear pressure of less than or equal to -150 mmH2O or a flat tympanogram and/or hearing threshold levels > 20 dB HL at 0.5 kHz and or 4.0 kHz are considered as indicative of ear pathology. Children failing the screening test should have a repeat test after 4-6 weeks at school and only those who do not pass on this occasion should be referred to an ENT department.