No abstract

No abstract

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 cm(3) for the 6- to 8-year age group significantly lower (p < 0.001) in comparison with 1.18 cm(3) for the 9- to 12-year age group. Also, girls had significant (p < 0.001) smaller ECV (mean 1.07 cm(3)) than boys (1.17 cm(3)). Auditory performance improves with rising age in school children.

In order to understand the repeated occurrences of auditory impairments caused by toy pistols, an analysis of the circumstances involved was performed at Justus-Liebig University of Giessen. The acoustic impact of toy pistols on the ear was determined with a special measuring system for impulse noise. Results were compared with the acoustic impacts of the G3 common rifle of the German military on the ear of the soldier. It was apparent that all of the five randomly selected types of toy pistols were much louder than the military rifle, if fired close to the ear. The current standard of the European Union related to the safety of toys (EN 71-1) tolerates peaks of impulse noise from toy pistols that are actually illegal for workplaces without auditory protection. Measurements showed that the toy pistols tested were even louder than that tolerated by the EU standard. Problems related to acute acoustic trauma caused by these toys are discussed using recent examples. In order to prevent such injuries, we suggest limiting the loudness of the "worst case" instead of using unrealistic measurements.

No abstract