Measuring the Reading-Attention Relationship: Functional Differences in Working Memory Activity During Single Word Decoding in Children With and Without Reading Disorder

Abstract

Working memory (WM) is linked to the development of reading skills and has been evidenced to contribute to reading comprehension difficulties in children with reading disorder (RD). Several converging models suggest WM to contribute to the development of foundational reading skills, but few studies have assessed this contribution in either typically developing readers (TD) or children with RD. In effort to bridge this gap, the current study identified whether a functional neuroimaging task could be used to identify changes in WM activity during single word reading in children with and without RD. Two groups of children (77 RD, 22 TD) aged 7-9 completed a functional magnetic resonance imaging (fMRI) task which paired reading and n-back trials to identify activation of a priori chosen regions of interest in the WM network during single word decoding. Trials consisted of words, pseudowords, and false font stimuli to assess WM activity between groups in relation to familiar words, unfamiliar words, and non-words. Exploratory analysis of behavioural WM correlates were assessed using measures of performance on the fMRI task as well as measures of verbal learning from the California Verbal Learning Test – Children’s version. Results show the fMRI task was able to identify WM network activity in both groups. In the RD group WM activity was indiscriminate to stimulus type and did not show any patterns of lateralization. In the TD group, WM activity was strongly left lateralized, and only detected during pseudoword reading, suggesting increases in WM activity during phonetic decoding only. Findings suggest the WM network may contribute differently to single word reading in children with and without RD and highlights the potential functional imaging may have in defining this relationship over the course of reading development.