Objective

Many studies report a deficit in working memory in children with Developmental Dyslexia (DD) and Developmental Coordination Disorder (DCD) compared to children with Typical Development (TD). In this study, we questioned the working memory profile of children with co-occurring Developmental Dyslexia and Developmental Coordination Disorder (DD-DCD). First, we hypothesized that children with DD would have a more substantial deficit in verbal working memory, while children with DCD would have a more substantial deficit in visuospatial working memory. For the comorbid group, we postulated a deficit in both the verbal and visuospatial domains. Second, we determined whether we could correctly distinguish between the four groups based on their working memory profiles.

Method

47 children with DD, 22 children with DCD, 27 children with DD-DCD, and 42 TD children aged from 7.6 to 12.6 years were tested on the phonological loop, the visuospatial sketchpad, and the central executive using the Digit Span and Wechsler’s Block-tapping tests.

Results

Children with DD had a deficit in verbal working memory including a specific deficit in the phonological loop and children with DCD had a deficit in visuospatial working memory. Comorbid children had poorer performance in verbal working memory (like group with DD) and in visuospatial working memory (like group with DCD). Exploratory cluster analysis resulted in four subgroups: (1) one cluster with good working memory performance made up of most of the TD children; (2) one cluster with a phonological loop deficit mainly made up of the children with DD; (3) one cluster with poor visuospatial working memory capacities mostly made up of the children with DCD (± DD) and (4) one cluster with average performance made up of children from all the groups.

Conclusion

Our results underline the importance of taking comorbidity into account when testing working memory in children with learning disabilities.

中文翻译：

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合并症对阅读障碍和发育协调障碍的工作记忆特征的影响。

目的

许多研究报告称，与典型发展（TD）儿童相比，发展性阅读障碍（DD）和发展性协调障碍（DCD）儿童的工作记忆不足。在这项研究中，我们质疑了同时发生的发展性阅读障碍和发展性协调障碍（DD-DCD）儿童的工作记忆特征。首先，我们假设DD儿童的言语工作记忆缺陷更大，而DCD儿童的视空间工作记忆缺陷更大。对于合并症组，我们假设言语和视觉空间领域均存在缺陷。其次，我们确定是否可以根据它们的工作记忆配置文件正确区分这四个组。

方法

对47名DD儿童，22名DCD儿童，27名DD-DCD儿童和42名7.6至12.6岁的TD儿童进行了音位环，视觉空间画板和中央执行器的数字跨度和Wechsler's Block测试攻牙测试。

结果

DD儿童的言语工作记忆不足，包括语音回路中的特定缺陷，而DCD儿童的视空间工作记忆不足。合并症儿童的言语工作记忆（如DD组）和视觉空间工作记忆（如DCD组）的表现较差。探索性的聚类分析得出四个子组：（1）一个由大多数TD子代组成的具有良好工作记忆性能的聚类；（2）一个由语音障碍儿童组成的语音音圈不足的集群；（3）视觉空间工作记忆能力较弱的一个群体主要由DCD（±DD）儿童组成，（4）平均表现的一个集群由各组儿童组成。

结论

我们的结果强调了在测试学习障碍儿童的工作记忆时考虑合并症的重要性。