Language and Learning Abilities in ‘Unaffected' School-Aged Siblings of Children with ASD

Background:

Researchers often use the term ‘unaffected’ to describe siblings of children with ASD who do not have ASD outcomes; however, emerging evidence suggests that the developmental trajectories of many of these siblings are atypical. They are at greater risk of delayed language acquisition and communication impairments during the preschool years, but less is known about their language abilities later in childhood. It is crucial to extend studies beyond early childhood to determine whether early language delays persist or resolve, as well as to examine later-developing skills such as pragmatics, phonological processing, and reading. As children grow and experience increasing psychosocial demands, these advanced language abilities become critical to academic and occupational success and social well-being.

Objectives:

To examine whether ‘unaffected’ school-aged siblings of children with ASD are at an increased risk for learning and language challenges: Do they fall below normative expectations on measures of phonological processing, reading, and pragmatic language?

Methods:

Eighteen participants (ages 8-11) with an older sibling with ASD were recruited from an ongoing longitudinal study. A standard battery of cognitive, structural language and social-communication measures was completed and the non-ASD status of all participants was determined by an expert clinician. The following primary outcome measures were completed: Comprehensive Test of Phonological Processing (CTOPP-2), Test of Word Reading Efficiency (TOWRE-2), Test of Pragmatic Language (TOPL-2), and Children’s Communication Checklist (CCC-2). A series of one-sample t-tests were conducted to evaluate whether siblings’ performance differed from the normative samples of these measures.

Results:

The siblings performed significantly below the normative sample in phonological memory (CTOPP-2 nonword repetition, t(17) = -5.80, p < .000) and phonological awareness (CTOPP-2 phoneme isolation, t(17) = -4.73, p < .000; blending words, t(17) = -2.54, p < .05). The siblings performed significantly above the normative sample on all four CCC-2 parent-report scales of pragmatics; Initiation (t(17) = 3.12, p < .01), Scripted Language (t(17) = 3.24, p < .01), Context (t(17) = 2.34, p < .05), and Non-verbal Communication (t(17) = 2.28, p < .05). Performance on our direct assessment of pragmatics, the TOPL-2, was in the average range; however, it was significantly lower than mean performance on the CELF-4 (t(15) = 4.63, p< .001). Further, three participants presented with profiles of pragmatic language impairment.

Conclusions:

This sample of siblings with non-ASD outcomes demonstrated impairments in both phonological memory and awareness. Hearing, remembering, and manipulating the sounds in language may take more effort and resources for these siblings. In contrast, word-level reading and rapid naming were intact. Relative to norms, no impairments were found on either a direct child assessment or parent-report measure of pragmatic language, and, somewhat surprisingly, the parent-report measure revealed pragmatic strengths. We recommend that this finding be interpreted cautiously, as differences in pragmatic abilities may not be obvious to all parents and may be exacerbated by differences in frames of reference. When comparing two direct language assessments, pragmatics were significantly lower than structural language. These mixed findings highlight pragmatics as an area for further research.