Identification of the factors associated with the severity of the speech production problems in children with comorbid speech sound disorder and developmental language disorder

Abstract

It has been suggested that factors such as auditory perception, oral motor skills, phonological awareness, and working memory are all associated with speech production problems in children with speech sound disorder (SSD) and developmental language disorder (DLD). However, it remains unclear whether the severity of the speech production problems in these children can be explained by an interaction among the aforementioned factors. The aim of this study was to determine which of these four factors best explain the severity of the speech production problems in children with SSD and DLD and whether an interaction between factors occurs. Forty-one children with SSD and DLD between 5 and 5;11 years old were selected. The number of phonological process errors was used as a measure of the severity of the speech production problems. The association between the number of phonological process errors and performance in auditory perception, oral motor skills, phonological awareness, and working memory along with the severity of the DLD was explored using univariate and multivariate regression models (with and without an interaction term). The results showed that the number of phonological process errors was largely explained by working memory and phonological awareness. An interaction between these two factors was also found. This means that working memory and phonological awareness interact to have an effect on the number of phonological process errors that is more than the sum of their parts. In addition, the severity of the DLD was significantly associated with the number of phonological process errors. These findings suggest that phonological awareness and working memory should be considered when assessing and treating children with comorbid SSD and DLD.