Estimates of interaural attenuation in children and the implications for masking in clinical audiometry

Abstract

Objective The aim of this study was to provide estimates of interaural attenuation (IA) in children, under clinical test conditions for supra-aural and insert earphones. Design This was a retrospective review of clinical audiograms for children aged 8 months to 16 years. Study sample There were between 2 and 21 subjects, depending on the transducer and stimulus frequency. Results For insert earphones, younger age groups had smaller IA estimates (mean 60 dB, minimum 40 dB) compared to older children (mean 78 dB, minimum 60 dB). The insert IA estimates for older children were similar to published adult IA data. There was no significant effect of age on the children’s estimated IA for supra-aural earphones. Conclusions Under the clinical conditions of this study, cross-hearing should be considered when the difference between the better ear and poorer ear not-masked air conduction thresholds are ≥ 40 dB for inserts with foam tips in children under 13 years. Smaller estimates of IA in younger children compared to older children may be due to difficulties achieving deep insertion of foam tips in smaller ears and less cooperative subjects under these conditions. Limitations of the study, including lack of bone conduction threshold data, are discussed.