Påverkar förskolemiljön barnens hörsel, uppmätt som otoakustiska distortionsprodukter?
Sammanfattning: The aim of this study was to assess if the preschool sound environment affects children's hearing, as measured by otoacoustic distortion products (DPOAE). To find out if the children’s hearing was affected by the time they spend in preschool, DPOAE amplitude in children with normal hearing function has been measured. Four repeated measurements were made in total: twice a day, in the mornings and afternoons, in the beginning of the week and in the end of the week. Change in DPOAE amplitude was analyzed with a two-way repeated ANOVA. The reliability of the measured DPOAE amplitude has been investigated by performing a test-retest measurement on eleven children, where DPOAE is measured twice immediately after each other. To investigate whether the sound environment in preschool can affect the child's hearing, the sound level has been measured using dosimeters (body-worn sound level meter) carried by the children. To assess if the sound pressure level measured for the children differ from the adults, the staff also carried dosimeters. A fixed dosimeter was placed as a reference hanging from the ceiling in the playroom where the children spent their time on the day of the measurements. DPOAE and sound level measurements have been performed at four preschools. DPOAE amplitude from 27-29 right ears and 30-31 left ears have been analyzed. The result shows a reduction of DPOAE amplitudes measured at 3000 Hz and 4000 Hz for the right ear. The amplitude reduction was seen between the measurements made early in the week and the measurements made late in the week. The other six of eight analyzed frequencies did not show a consistent decline in amplitude over the week. We did not find any significant differences between morning and afternoon measurements, nor for measurements in the left ear. Due to the number of statistical analyzes that was carried out, we cannot rule out type-1 errors. There may also possibly be an influence on the amplitude caused by an altered middle ear status during the week. Test-retest measurement when measuring DPOAE, shows no significant difference between first and second insertion of the probe. This indicates that DPOAE can be performed on children at repeated occasions without large variance caused by handling. The sound level measurements in preschools showed that 42% of the children were exposed to levels above 80 dB LAeq during playtime indoors and that 18% of these children were exposed to levels above 85 dB LAeq. The teachers were exposed to 80 dB LAeq in 33% of the measurements.This study was made in collaboration with Maja Jansson, a master’s student in Applied Acoustics at Chalmers University of Technology. Her work is published with the title: The sound environment at preschools and how it may affect children’s hearing (Jansson, 2017).
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