City Research Online

Abstract

Background: To support children who have Developmental Language Disorder (DLD) with effective interventions, it is important to understand the nature of their difficulties. Working memory difficulties are found in most children with DLD. A key element of the working memory system is phonological encoding, the process of transforming a visual stimulus (such as a word or picture) into a verbal label. Phonological encoding is important for effective working memory, as verbal material is easier to remember, is strongly implicated in word learning, and can be measured through the presence of the ‘phonological similarity effect’ (PSE). Little is known about the PSE in children with DLD. The aim was to investigate whether phonological encoding and children’s use of verbal rehearsal strategies, used to support this process, were reduced in children with DLD compared to their typically developing (TD) peers. In addition, several processes that are known to be associated with working memory were also investigated, to consider if they predicted phonological encoding abilities.

Method: Children aged 6-7 (n=69) and 9-10 years (n = 63), some typically developing (n=59) and some with DLD (n = 73) played a laptop-based working memory game. Pictures of common objects were presented visually, and recall was via a pointing method, so the task could be carried out without using phonological encoding. Children recalled which pictures they had seen, in serial order, by tapping images of them on the screen. This was repeated for two lists of pictures: those with either phonologically similar or phonologically dissimilar names. The discrepancy between recall of each of those lists was used to calculate the ‘PSE’ and infer the presence of phonological encoding. The logic was that, if phonological encoding were used, confusion would arise in remembering the names of items that were phonologically similar. Afterwards the children repeated the task at their maximum memory span levels and were asked to self-report which, if any, verbal rehearsal strategy they used to help them remember the pictures.

Results: Children with DLD at both ages showed a significantly reduced PSE compared to their TD peers, and this effect was found even when using a proportional score to take account of children who had a low memory span. In addition, children with DLD reported using ‘complex’ verbal rehearsal strategies less often than their TD peers. There was a lack of significant associations between measures known to correlate with working memory and PSE, in children with or without DLD.

Conclusions: In this investigation, children with DLD showed a significantly lower PSE and significantly reduced use of verbal rehearsal strategies than TD peers. Both findings suggests that they are less likely to use phonological encoding than their TD peers.

Implications: The research provides new findings which could have implications for future clinical practice e.g., language interventions and the adaptation of classrooms to better support children with DLD and working memory difficulties.

Publication Type:	Thesis (Doctoral)
Subjects:	L Education R Medicine > RJ Pediatrics > RJ101 Child Health. Child health services
Departments:	School of Health & Psychological Sciences > Language & Communication Science School of Health & Psychological Sciences > School of Health & Psychological Sciences Doctoral Theses Doctoral Theses

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