Noise Equally Degrades Central Auditory Processing in 2- and 4-Year-Old Children.

Purpose: The aim of this study was to investigate developmental and noise-induced changes in central auditory processing indexed by event-related potentials in typically developing children. Method: P1, N2, and N4 responses as well as mismatch negativities (MMNs) were recorded for standard syllables and consonants, frequency, intensity, vowel, and vowel duration changes in silent and noisy conditions in the same 14 children at the ages of 2 and 4 years. Results: The P1 and N2 latencies decreased and the N2, N4, and MMN amplitudes increased with development of the children. The amplitude changes were strongest at frontal electrodes. At both ages, background noise decreased the P1 amplitude, increased the N2 amplitude, and shortened the N4 latency. The noise-induced amplitude changes of P1, N2, and N4 were strongest frontally. Furthermore, background noise degraded the MMN. At both ages, MMN was significantly elicited only by the consonant change, and at the age of 4 years, also by the vowel duration change during noise. Conclusions: Developmental changes indexing maturation of central auditory processing were found from every response studied. Noise degraded sound encoding and echoic memory and impaired auditory discrimination at both ages. The older children were as vulnerable to the impact of noise as the younger children. Supplemental materials: https://doi.org/10.23641/asha.5233939.

Linguistic multi-feature paradigm as an eligible measure of central auditory processing and novelty detection in 2-year-old children.

This study evaluated whether the linguistic multi-feature paradigm with five types of speech-sound changes and novel sounds is an eligible neurophysiologic measure of central auditory processing in toddlers. Participants were 18 typically developing 2-year-old children. Syllable stimuli elicited significant obligatory responses and syllable changes significant MMN (mismatch negativity) which suggests that toddlers can discriminate auditory features from alternating speech-sound stream. The MMNs were lateralized similarly as found earlier in adults. Furthermore, novel sounds elicited a significant novelty P3 response. Thus, the linguistic multi-feature paradigm with novel sounds is feasible for the concurrent investigation of the different stages of central auditory processing in 2-year-old children, ranging from pre-attentive encoding and discrimination of stimuli to attentional mechanisms in speech-like research compositions. As a conclusion, this time-efficient paradigm can be applied to investigating central auditory development and impairments in toddlers in whom developmental changes of speech-related cortical functions and language are rapid.