Artikel
Sensitivity to interaural time differences as a function of age and shape of acoustic stimuli in normal hearing humans
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Veröffentlicht: | 18. März 2025 |
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Gliederung
Text
Horizontal sound localization is based on two important binaural cues: interaural time differences (ITDs) and interaural level differences (ILDs). In normal hearing (NH) adults, the ITD sensitivity threshold at 250 Hz is around 25–30 µs [1]. However, the sensitivity to binaural cues can be influenced by various factors such as hearing experience, developmental state or the type of the acoustic stimulus [2], [3], [4]. The development of ITD sensitivity across age and its dependency on stimulus parameters are still under research and were investigated in this study.
Eleven NH (<20 dB HL) children (Ø 9.05 years old) and 10 NH adults (Ø 34.03 years old) were tested on sound lateralization in a gamified setup using headphones. A 0.5 s long tone burst at 250 Hz and a rising slope of 4 ms or 100 ms was used as acoustic stimulus. Participants were tested for different ITDs of ±\'7b25, 50, 100, 200, 400, 800\'7d µs. ITD just-noticeable differences (JNDs) were calculated for the different test conditions using psychometric functions.
NH adults demonstrated significantly better ITD JNDs (Ø 64.79 µs) compared to NH children (Ø 93.61 µs) for both slope conditions. For NH children, ITD sensitivity showed a positive correlation with age under both test conditions, indicating developmental improvement. Notably, both cohorts exhibited significantly better ITD JNDs when the auditory stimuli were presented with a rising slope of 4 ms (children: Ø 92.07 µs, adults: Ø 55.78 µs) rather than 100 ms (children: Ø 113.89 µs, adults: Ø 73.28 µs).
In conclusion, auditory networks for ITD-based spatial hearing are still maturing in early childhood [DTW1] , resulting in significantly poorer ITD sensitivity compared to mature, adult networks. Regardless of developmental stage, better ITD sensitivity was achieved with auditory stimuli that contained strong onset ITD information (4 ms rising slope), confirming the importance of onset ITD sensitivity for optimal spatial hearing.
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