Immediate memory of list items and their order in children with or without dyslexia: Constancies and differences across elementary school grades

Children with dyslexia, with or without concomitant developmental language disorder (DLD), have difficulty retaining the order of items presented in lists for immediate recall. The evidence to date, however, has not been systematic in the comparison of measures designed to isolate item and serial position information for both verbal and nonverbal tasks in children across age groups. We report on such a study in an immediate memory test battery including standard and running span measures for series of digits, locations, and shapes. We examined 677 English-speaking, United States children in Grades 1-4, categorized through standardized tests (rather than clinical diagnosis): 470 with typical development, 165 with dyslexia only, and 42 with both dyslexia and developmental language disorder (dyslexia + DLD). Too few children had DLD only to allow statistical analysis. Along with a measure of the number of items recalled regardless of serial position, we examined the reduction in memory when serial position errors were considered, in both ratio and difference measures. In one test, children with dyslexia alone showed smaller gaps in performance than those with typical development in older age groups, whereas one performance gap in children with dyslexia + DLD instead appeared larger in older age groups. In an interesting dissociation, group differences for standard digit span emerged only in measures of item retention, whereas group differences for other measures were largest for serial position information. Assessment of performance should be designed to consider the potential importance of verbal item capacity and of verbal and nonverbal serial position information.