Pure-tone auditory threshold in school children
To determine pure-tone auditory thresholds, 197 screened children at a typical primary school in a German town (~70,000 inhabitants) were examined. All children underwent a tympanometry and an audiometry at 17 frequencies from 125 to 16 kHz. Regarding age effects, two groups (6–8 and 9–12 years) were analyzed. The cross-sectional research was supplemented by a follow-up study with 35 children of the first graders 3 years later. School children have the poorest hearing sensitivity at low frequencies (below 1 kHz) and the best sensitivity at the extended high frequencies above 8 kHz. Hearing thresholds are rising significantly with age. Through all frequencies, averaged improvements were 3.8 dB (right ear) and 3.7 dB (left ear) at the cross-sectional study and 3.7 dB (right ear) and 5.1 dB (left ear) at the longitudinal study. The overall deviation (left and right) from the standard thresholds for adults were 7.4 and 3.6 dB for the younger and older age groups, respectively. The ear canal volume (ECV) measured by tympanometric tests was at mean with 1.06 cm3 for the 6- to 8-year age group significantly lower (p < 0.001) in comparison with 1.18 cm3 for the 9- to 12-year age group. Also, girls had significant (p < 0.001) smaller ECV (mean 1.07 cm3) than boys (1.17 cm3). Auditory performance improves with rising age in school children.