Phonological processing skills in children with speech sound disorder: A multiple case study approach

Children with speech sound disorder (SSD) are at increased risk of reading difficulties due to poor phonological processing skills. However, the extent to which children with SSD demonstrate weaknesses on specific or all phonological processing tasks is not well understood.

To examine the phonological processing abilities of a clinically identified sample of children with SSD, with and without reading difficulties. To determine the extent to which the proportion of children with concomitant SSD and reading difficulties exhibited weaknesses in specific areas of phonological processing, or a more general phonological deficit.

Data were obtained from 157 school-aged children (M_age = 77 months, SD = 7.01) in receipt of school-based speech therapy. Approximately 25% of the sample was identified as poor readers, based on a standardized measure of word decoding. We compared the proportion of children who scored at or below 1 SD below the mean, or the bottom 16th percentile, on measures of phonological awareness, rapid automatized naming and verbal short-term memory among those identified as poor readers and good readers.

Children with SSD demonstrated a range of phonological processing difficulties, particularly on the measure of verbal short-term memory. No specific skill differentiated groups of children with SSD with and without reading difficulties; however, those classified as poor readers on the word-decoding measure exhibited more widespread difficulties, even after controlling for language ability.

Results support a cumulative risk model such that children with SSD and reading difficulties are likely to demonstrate generally poor phonological processing abilities.

What is already known on the subject Children with SSD are at heightened risk of reading difficulties, particularly if their SSD persists into school age. However, not all children with SSD experience reading problems. Research aimed at determining which children are at the highest risk is mixed as to how best to identify which children with SSD are most likely to experience reading difficulties. What this paper adds to existing knowledge The study used a multiple case study approach to determine if performance on phonological processing skills might differentiate children with SSD who were poor readers from those who were good readers. As a group, children with SSD exhibited poor verbal short-term memory but relatively intact rapid automatized naming skills. No one phonological processing skill differentiated children who were poor readers from good readers. However, children with reading difficulties appeared to experience more general difficulties across phonological processing tasks, even after controlling for language abilities. What are the potential or actual clinical implications of this work? A single deficit (i.e., speech sound production) is not sufficient data to make a complete diagnosis or treatment decisions. Multiple sources of data, including several aspects of phonological processing, should be obtained to understand reading risk in children with SSD.