Effect of pre-school sound exposure on children's hearing function: results from preparatory studies assessing hearing function by distortion product otoacoustic emissions.

Abstract

Objective: This study investigated the potential impact of sound exposure in preschools on children's hearing function by measuring distortion product otoacoustic emissions (DPOAE) over time.

Design: A longitudinal repeated-measures approach was employed to evaluate how DPOAE amplitudes varied with sound exposure and pre-school attendance duration, analysed using general estimation equation (GEE) modelling.

Study sample: The sample included 62 children aged three to six years attending preschools. Sound exposure levels and DPOAE amplitudes were measured during time being indoor.

Results: Average indoor sound levels (time indoors (_Ti)) were 81 dB LAeq_Ti, with highest noise events reaching 112 dB LAFmax. A total of 31 measurements (52%) exceeded 80 dB LAeq_Ti. GEE analysis showed a significant decrease in DPOAE amplitudes at 6 and 8 kHz in the right ear in relation to sound exposure levels, suggesting a sound level-dependent effect. Time spent in pre-school revealed a decrease in DPOAE amplitudes at 3 and 4 kHz in the right ear over the day and week, indicating cumulative effects of sound exposure.

Conclusions: The findings suggest that pre-school sound exposure may adversely affect children's hearing, particularly at higher frequencies and over time. Further research is needed to validate these results and explore long-term implications of early-age noise exposure.