Temporal resolution efficiency and auditory stream segmentation development

Abstract: Background: The ability to hear changes in a sound envelope is called temporal resolution and is assumed to have a key role in binaural speech segmentation. The development of temporal resolu-tion is not fully explored, but studies indicate that it develops into adult-like efficiency at approxi-mately 8-13 years of age, while binaural speech segmentation has an extended development up until approximately 13-16 years of age. Method: A group of children (9-12 years of age) were compared to a group of 16 young adults. Temporal resolution was tested with a monaural non-speech amplitude modulation (AM) test at six modulation rates (10, 50, 75, 125, 150 and 250 Hz). Auditory stream segmentation was investigated with the binaural Listening in Spatialized Noise Sentence Test (LiSN–S). The purpose was to in-vestigate in what age-span these abilities become adult-like, if there were development differences depending on modulation rate and if there was a correlation between the tests. Results: A repeated measures ANOVA showed a significant difference between the two groups both on the AM-test (p=0.001) and LiSN-S test (p=0.002). A trend could also be seen that the 11-12 year old children (n=11) scored higher on the higher modulation rates compared to the lower ones. A positive significant correlation between LiSN-S spatial advantage score and the AM test at the modulation rates 50, 150 and 250 Hz was also found. Conclusions: The results indicate that temporal resolution efficiency is still developing at 9-12 years of age, but that children can reach adult-like temporal resolution efficiency at about 11-12 years of age, especially at higher modulation rates (between 150-250 Hz). The last steps of the anatomical maturation is continuing until approximately the age of 11-12, which corresponds well to these findings. The correlation between the tests might indicate that an efficient temporal resolu-tion is an advantage when use spatial cues.