Department of Speech and Hearing Science, The Ohio State University, Columbus, Ohio, USA.
Sugar House Health Center, University of Utah, Salt Lake City, Utah, USA.
Int J Lang Commun Disord. 2024 Nov-Dec;59(6):2896-2910. doi: 10.1111/1460-6984.13120. Epub 2024 Oct 4.
Accurate nonword repetition (NWR) is contingent on many underlying skills, including encoding, memory and motor planning and programming. Though vowel errors are frequently associated with childhood apraxia of speech (CAS), several recent studies have found that children with developmental language disorder (DLD) produce high rates of vowel errors in NWR tasks.
This retrospective analysis explored whether the overall frequency and types of vowel errors produced in NWR distinguish children with DLD, children with CAS, children with speech sound disorder (SSD) and children with typical development (TD).
We present data for 24 children (six per DLD, CAS, SSD and TD groups), ranging in age from 50-92 months. Children with DLD, CAS and SSD showed similar articulation scores and children with DLD and children with CAS showed similar expressive language scores. Total vowel errors, total monophthong errors, monophthong substitutions, diphthongization errors, total diphthong errors, diphthong substitutions and diphthong reduction errors were calculated by syllable length and group. Repeated measures analyses of variance were used to examine group differences.
Children with DLD and children with CAS produced a higher frequency of total vowel errors compared to children with TD. Children with DLD produced more total monophthong errors than children with TD. Children with DLD and children with CAS produced more total diphthong errors than children with TD. For children with DLD, these were characterised by diphthong substitutions. For children with CAS, these were characterised by diphthong substitutions and diphthong reduction errors. For all measures, error rates in children with SSD did not significantly differ from any of the other three groups.
Preliminary evidence indicates that children with DLD and children with CAS both show high rates of vowel errors in NWR tasks and weaknesses in encoding and memory. For children with CAS, additional motor planning difficulties are associated with an increased likelihood to reduce diphthongs. Children with SSD show more mild processing difficulties than children with DLD and children with CAS, though they do not perform as well as TD peers. Future work should replicate and further specify the processing weaknesses that affect vowel accuracy in NWR tasks in a larger sample.
What is already known on the subject Nonword repetition (NWR) tasks are often included in diagnostic batteries to identify children with developmental language disorder (DLD). Poor performance on these tasks have historically been attributed to phonological working memory deficits in children with DLD. However, repeating nonwords relies on a number of underlying processing skills and many of these skills are affected to varying degrees in children with speech and language disorders. An in-depth analysis of vowel errors has the potential to reveal the shared as well as specific underlying processing weaknesses in children with DLD, children with childhood apraxia of speech (CAS) and children with speech sound disorder (SSD). What this paper adds to existing knowledge We found that children with DLD and children with CAS show low vowel competence compared to children with typical development. A nuanced examination of vowel error types further revealed that children with DLD and children with CAS show weaknesses in encoding and memory. Motor planning and programming weaknesses were unique to CAS. Children with SSD show more mild processing deficits and their performance did not significantly differ from any of the other three groups. What are the clinical implications of this work? Examining the types of vowel errors produced by children with DLD, children with CAS and children with SSD in NWR allows us to further specify the underlying processing weaknesses that differentiate these three groups. This research informs theoretical accounts of language processing in children with different types of speech and language disorders and has the potential to improve the diagnostic utility of NWR tasks.
准确的非词重复（NWR）取决于许多潜在技能，包括编码、记忆和运动计划和编程。尽管元音错误经常与儿童运动性言语障碍（CAS）有关，但最近的几项研究发现，语言发育障碍（DLD）儿童在 NWR 任务中产生高比率的元音错误。
本回顾性分析探讨了 DLD 儿童、CAS 儿童、言语障碍（SSD）儿童和典型发育（TD）儿童在 NWR 中产生的整体元音错误频率和类型是否存在差异。
我们为 24 名儿童（每组 6 名，DLD、CAS、SSD 和 TD 组）呈现数据，年龄从 50-92 个月不等。DLD 儿童、CAS 儿童和 SSD 儿童的发音评分相似，DLD 儿童和 CAS 儿童的表达性语言评分相似。通过音节长度和组计算总元音错误、总单元音错误、单元音替换、双元音化错误、总双元音错误、双元音替换和双元音减少错误。使用重复测量方差分析来检查组间差异。
与 TD 儿童相比，DLD 儿童和 CAS 儿童产生的总元音错误频率更高。DLD 儿童产生的总单元音错误多于 TD 儿童。DLD 儿童和 CAS 儿童产生的总双元音错误多于 TD 儿童。对于 DLD 儿童，这些错误表现为双元音替换。对于 CAS 儿童，这些错误表现为双元音替换和双元音减少错误。对于所有测量，SSD 儿童的错误率与其他三组均无显著差异。
初步证据表明，DLD 儿童和 CAS 儿童在 NWR 任务中都表现出高比率的元音错误，以及在编码和记忆方面的弱点。对于 CAS 儿童，额外的运动计划困难与增加减少双元音的可能性有关。与 DLD 儿童和 CAS 儿童相比，SSD 儿童表现出更轻微的加工困难，尽管他们的表现不如 TD 同龄人。未来的工作应该在更大的样本中复制和进一步确定影响 NWR 任务中元音准确性的处理弱点。
关于这个主题已经知道的内容：非词重复（NWR）任务通常包含在诊断电池中，以识别语言发育障碍（DLD）儿童。这些任务的表现不佳历史上归因于 DLD 儿童的语音工作记忆缺陷。然而，重复非词依赖于许多潜在的处理技能，许多这些技能在言语和语言障碍儿童中受到不同程度的影响。对元音错误的深入分析有可能揭示 DLD 儿童、CAS 儿童和 SSD 儿童共同的以及特定的潜在处理弱点。本文对现有知识的增加：我们发现 DLD 儿童和 CAS 儿童的元音能力与 TD 儿童相比较低。对元音错误类型的细致检查进一步表明，DLD 儿童和 CAS 儿童在编码和记忆方面存在弱点。运动计划和编程弱点是 CAS 特有的。SSD 儿童表现出更轻微的加工缺陷，其表现与其他三组均无显著差异。这对临床有何影响？检查 DLD 儿童、CAS 儿童和 SSD 儿童在 NWR 中产生的元音错误类型，使我们能够进一步确定区分这三组的潜在处理弱点。这项研究为不同类型的言语和语言障碍儿童的语言处理理论提供了信息，并有可能提高 NWR 任务的诊断效用。
