Enriched speech input to promote language development in children with sensorineural hearing loss: Neural and behavioral evidence

点击翻译按钮获取中文摘要

Children with sensorineural hearing loss experience problems in understanding and producing speech sounds. These linguistic difficulties occur despite early diagnosis and improved hearing-device treatment and predominantly affect speech sounds within the high-acoustic frequency (HAF) range (>2 kHz), such as consonants /s/, /t/, and /f/. As these consonants distinguish words and, in German, also mark morpho-syntactic dependencies, these problems have detrimental effects on children’s word and morpho-syntactic learning. Our research aims at investigating whether 1- to 3-year-old children with sensorineural hearing loss benefit in their deficient speech perception when exposed to enriched speech. In three electrophysiological (EEG) experiments and two eye-tracking experiments, we test the hypothesis that perception is boosted for speech that contains additional acoustic cues to HAF consonants. In the first EEG experiment, children listen to naturalistic infant-directed speech in which speech sounds are highlighted, as caregivers typically speak slower and with stronger pitch modulations to young children. In the other EEG and eye-tracking experiments, consonant-amplification in infant-directed speech is used as specific acoustic enrichment, where HAF consonants are additionally amplified in their high-frequency range. Perceptual improvement from both kinds of enriched speech versus adult-directed speech (without enrichment) will be quantified by state-of-the-art analysis techniques: In addition to traditional event-related analyses of brain responses, we will analyze speech-brain coherence, specifically neural tracking at the speech-sound rate, across speech types with and without enrichment. Using multivariate-temporal response functions, we will compare brain responses to high versus low-frequency consonants under different enrichment conditions. Moreover, analyses of pupil dilation and preferential looking will test for children’s potential benefit from enriched speech in their consonant discrimination. Neural and behavioral correlates of HAF consonant perception will be longitudinally (after 12 months) related to children’s consonant articulation in a speech elicitation task. Finally, we will employ questionnaires and behavioral tests to study whether the proposed perceptual benefit from enriched speech is mediated by children’s overall language skills (e.g., vocabulary and grammar knowledge) and factors in their learning environment (e.g., caregiver-speech modifications and music-exposure at home). EEG and eye-tracking measures of children with sensorineural hearing loss will be compared to children with normal hearing, matched in age, sex, and socioeconomic status. Our research provides a first step in evaluating the potential impact of enriched speech in ameliorating speech perception deficits in children with sensorineural hearing loss, and may inform low-cost family-centered interventions to stimulate these children’s language development.