Evaluation of auditory lateralization ability and its development in normal children with 8 to 11 years of age

Auditory lateralization is a binaural phenomenon that is the result of processing of interaural time and intensity cues in the central auditory system. The main advantage of this phenomenon in human is understanding speech in noisy environments due to the auditory sciene analysis and cocktail party effects. The aim of the present study was to assess the auditory lateralization ability in normal children. Participants were 80 normal school age children (8-11 years) of both genders، 42 girls and 38 boys. Lateralization functions were determined by interaural time difference (ITD) ranging from -880 to +880 µs and interaural intensity difference (IID) ranging from -10 to +10 dB for high-pass and low-pass noise. Interaural intensity difference lateralization functions were linear، while the interaural time difference lateralization functions were S-shaped with a clear linear component from -220 to +220 µs and with an asymptote from -440 to -880 µs and +440 to +880 µs. Generally، interaural intensity difference errors were significantly less than interaural time difference tasks (p<0. 0001). Age effect was only present in interaural time difference tasks (p=0. 001). According to these results، children with the age of 11 years performed better in lateralization using interaural time difference cues compared to other children; whereas there was no difference in performance in all ages when using interaural intensity difference cues.