Reading disabilities and speech delays: Literacy outcomes in children with Speech Sound Disorder

By Nicole Hess MS, CCC-SLP

Friday’s Column “Focus on Language” by Nicole Hess.

One of my jobs as a speech language pathologist is to evaluate children who have speech delays, and one of the most common questions that I answer for parents is whether their child will have problems learning how to read. It has been long held that children with speech sound disorder (SSD) have poorer outcomes in reading ability (reading disability, RD). In fact, research suggests that SSD and reading disabilities have a comorbidity rate of 25-30%. It is thought that an underlying phonological processing deficit is responsible for both RD and SSD. However, research also points towards a more complex association between SSD and RD. For example, when a child’s difficulty only lies in articulation and does not involved language ability, literacy outcomes are quite good. However, if the deficits include vocabulary development (semantics) or sentence construction (syntax) the child is more likely to develop a reading disability. Yet, previous research has also shown that that if a child’s speech (e.g., articulation) delays persist to when the child is beginning to read, such delays will have an impact on reading skills. Therefore, it is unclear whether reading disabilities are affected by language delays in the context of SSD, by persistent speech difficulties, or by a combination of these two factors.
Peterson and colleagues published an article in the Journal of Speech, Language and Hearing Research last month that investigated whether it was language ability or persistence of speech sound disorder that contributed to the development of reading disorders. They took one hundred twenty-three 7- to 9-year-old children, including 86 with a history of SSD and 37 with normative language development (controls). The children completed various measures of language and reading ability. The original assessment of these children occurred when they were between 5-6 and then again at 7-9.

As expected, the children with SSD did more poorly than the controls in reading ability. Within this group, language impairment, but not SSD persistence, predicted poor literacy outcomes. This would suggest that SSD persistent does not play a role in reading development. However, SSD persistence was related to deficits in phonological awareness, which is in turn associated with some types of reading difficulties. In addition, the authors found that those with SSD persistence AND a language impairment (LI) had the worst outcomes, with 66% of these children also showing a reading disability.

Their other hypothesis was that broad language ability at the age of 5-6 would predict later literacy better than persistence of speech errors. This was also confirmed. It appears that phonological processing alone does not predict reading ability. Instead, multiple deficits is a better predictor of reading disorders. Children who had only a SSD did as well as the controls on reading ability tests.

The study had a few limitations. It did not assess reading ability in children older than 7-9. Since reading demands become more complex in later years, it is unknown if SDD persistence alone would affect future reading abilities.

For the working speech language pathologist it is critical that we look at both language and articulation when a child comes to us with a speech delay. For parents, it is also important to ask about the childs broader language abilities even when, on the surface, it appears that the child only has an articulation/speech impairment. Thus, it is important to know if there are underlying language issues that need to be addressed in order to prevent reading difficulties. Most importantly, nonverbal intelligence, vocabulary development and syntax should be targeted.

The reference: Peterson, R., Pennington, B., Shriberg, L., & Boada, R. (2009). What influences literacy outcome in children with Speech Sound Disorder? Journal of Speech, Language, and Hearing Research DOI: 10.1044/1092-4388(2009/08-0024)