Through Children’s Ears

Abstract

Background. In Sweden, nearly all children aged 4 to 6 attend preschool, making it a major source of daily indoor sound exposure. Existing standards are derived from adult occupational contexts and may not reflect children’s exposure or perception. Methods. This thesis employed child-centred approaches across three studies. Paper I combined child-worn dosimeter data (LAeqTi, LAFmax, LAFmax,95) with cochlear function assessed by distortion-product otoacoustic emissions (DPOAEs) in a repeated-measures design. Paper II applied the same design using pressurised DPOAEs (pDPOAEs) with systematic tympanometry to reduce middle-ear influence. Paper III analysed binaural recordings with Child and Adult Head and Torso Simulators (HATS) to derive Loudness and Sharpness, compared with children’s responses from the Inventory of Noise and Children’s Health (INCH) interview. Results. Mean personal exposure was 80–81 dB LAeqTi, with LAFmax often exceeding 115 dB. In Paper I, higher exposure was associated with reduced DPOAE amplitudes at high frequencies. Paper II found no consistent exposure–response patterns, although pDPOAEs varied by time of day and sex. Paper III found no robust statistical associations; however, about one quarter to one third of the children reported disturbing sounds accompanied by negative emotions, while most rated their overall well-being as positive. Conclusions. Preschool children are exposed to sound levels that approach or at times surpass adult occupational and environmental limits. Paper I showed frequency-specific reductions in cochlear responses consistent with short-term outer hair cell effects. Paper II, using pDPOAEs with systematic tympanometry, found no exposure–response links; observed amplitude increases later in the day and week probably reflected selective retention after tympanometric exclusions. Paper III found no statistical associations; however, a minority of children frequently reported disturbing sounds accompanied by negative emotions. Together, the studies demonstrate the feasibility of child-centred dosimetry, otoacoustic emission testing, and psychoacoustic modelling, and underline the need for child-specific acoustic models, event-based metrics, and closer temporal alignment of exposure and outcomes to guide protective measures in early childhood settings.