Sound discrimination and explicit mapping of sounds to meanings in preschoolers with and without developmental language disorder

To investigate links between sound discrimination and explicit sound-meaning mapping by preschoolers with and without developmental language disorder (DLD). We tested 26 children with DLD and 26 age- and gender-matched peers with typical language development (TLD). Inclusion was determined via results of standardised assessments of language and cognitive skills and a hearing screening. Children completed two computerised tasks designed to assess pitch and duration discrimination and explicit mapping of pitch- and duration-contrasting sounds to objects. Children with TLD more successfully mapped pitch categories to meanings than children with DLD. Children with TLD also showed significantly better overall sound discrimination than children with DLD. Sound-discrimination scores were marginally associated with overall sound-meaning mapping in multivariate analyses of covariance (MANCOVAs). Correlation tests indicated significant associations between discrimination and mapping, with moderate to large effect sizes. Thus, significant sound-discrimination differences between the groups may contribute to differences in sound-meaning-mapping accuracy. Children with DLD had more difficulty mapping sound categories to meanings than TLD peers. We discuss possible explanations for this finding and implications for theoretical accounts of the aetiology of DLD.

本研究旨在探究伴与不伴发育性语言障碍（developmental language disorder, DLD）的学龄前儿童在声音辨别能力与显性声音-意义映射之间的关联。本研究共测试了26名发育性语言障碍儿童，以及26名年龄与性别匹配的典型语言发育（typical language development, TLD）对照儿童。纳入标准由语言与认知能力标准化评估结果及听力筛查结果确定。受试儿童完成两项计算机化任务，分别用于评估音高辨别与时长辨别能力，以及将音高和时长存在差异的声音映射至对应物体的显性声音-意义映射能力。典型语言发育组儿童将音高类别映射至语义的表现优于发育性语言障碍组儿童。典型语言发育组儿童的整体声音辨别能力也显著优于发育性语言障碍组儿童。在多元协方差分析（multivariate analyses of covariance, MANCOVAs）中，声音辨别得分与整体声音-意义映射能力存在微弱关联。相关性检验结果显示，辨别能力与映射能力之间存在显著关联，效应量处于中等至较大水平。因此，两组间显著的声音辨别能力差异，可能是导致声音-意义映射准确率差异的重要因素。发育性语言障碍组儿童在将声音类别映射至语义方面，较典型语言发育组同伴面临更多困难。本研究将讨论该研究结果的可能解释，以及其对发育性语言障碍病因学理论阐释的启示。