Background and aims

Children with developmental language disorder (DLD) often perform below their typically developing peers on verbal memory tasks. However, the picture is less clear on visual memory tasks. Research has generally shown that visual memory can be facilitated by verbal representations, but few studies have been conducted using visual materials that are not easy to verbalize. Therefore, we attempted to construct non-verbalizable stimuli to investigate the impact of working memory capacity.

Method and results

We manipulated verbalizability in visual span tasks and tested whether minimizing verbalizability could help reduce visual recall performance differences across children with and without developmental language disorder. Visuals that could be easily verbalized or not were selected based on a pretest with non-developmental language disorder young adults. We tested groups of children with developmental language disorder (N = 23) and their typically developing peers (N = 65) using these high and low verbalizable classes of visual stimuli. The memory span of the children with developmental language disorder varied across the different stimulus conditions, but critically, although their storage capacity for visual information was virtually unimpaired, the children with developmental language disorder still had difficulty in recalling verbalizable images with simple drawings. Also, recalling complex (galaxy) images with low verbalizability proved difficult in both groups of children. An item-based analysis on correctly recalled items showed that higher levels of verbalizability enhanced visual recall in the typically developing children to a greater extent than the children with developmental language disorder.

Conclusions and clinical implication: We suggest that visual short-term memory in typically developing children might be mediated with verbal encoding to a larger extent than in children with developmental language disorder, thus leading to poorer performance on visual capacity tasks. Our findings cast doubts on the idea that short-term storage impairments are limited to the verbal domain, but they also challenge the idea that visual tasks are essentially visual. Therefore, our findings suggest to clinicians working with children experiencing developmental language difficulties that visual memory deficits may not necessarily be due to reduced non-verbal skills but may be due to the high amount of verbal cues in visual stimuli, from which they do not benefit in comparison to their peers.

中文翻译：

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视觉刺激的较低语言能力调节有无发育性语言障碍儿童对工作记忆能力估计的差异

背景和目标

患有发育性语言障碍 (DLD) 的儿童在言语记忆任务上的表现往往低于正常发育的同龄人。然而，视觉记忆任务的情况不太清楚。研究普遍表明，视觉记忆可以通过语言表达来促进，但很少有研究使用不易语言表达的视觉材料进行。因此，我们试图构建不可语言化的刺激来研究工作记忆容量的影响。

方法与结果

我们在视觉跨度任务中操纵了语言能力，并测试了最小化语言能力是否有助于减少有和没有发育性语言障碍的儿童的视觉回忆表现差异。根据对非发育性语言障碍年轻人的预测试，选择了可以很容易地用语言表达或不能用语言表达的视觉效果。我们测试了患有发育性语言障碍的儿童组 (N = 23) 和他们正常发育的同龄人 (N = 65) 使用这些高和低的可语言化视觉刺激类别。患有发育性语言障碍的儿童的记忆跨度因不同的刺激条件而异，但至关重要的是，尽管他们对视觉信息的存储能力几乎没有受到损害，患有发育性语言障碍的儿童仍然难以用简单的图画回忆起可表达的图像。此外，事实证明，两组儿童都很难回忆起语言能力低的复杂（星系）图像。对正确回忆项目的基于项目的分析表明，与有发育性语言障碍的儿童相比，较高水平的语言能力在更大程度上增强了正常发育儿童的视觉回忆。

结论和临床意义：我们认为，与发育性语言障碍儿童相比，正常发育儿童的视觉短期记忆可能在更大程度上由言语编码介导，从而导致视觉能力任务的表现较差。我们的研究结果对短期存储障碍仅限于语言领域的观点提出了质疑，但它们也挑战了视觉任务本质上是视觉的观点。因此，我们的研究结果表明，与语言发育障碍儿童打交道的临床医生认为，视觉记忆缺陷不一定是由于非语言技能下降所致，而可能是由于视觉刺激中大量的语言暗示，他们无法从中受益与同龄人相比。