Abstract/Summary

Background: SLI is heterogeneous and identifying subgroups within it may help explain the aetiology of the condition. Phonological processing abilities distinguish between children with SLI who do and do not have reading decoding impairments (RDI). Aims: This study aims to probe different levels of phonological processing in children with SLI with and without RDI to investigate the cognitive basis of these differences. Methods & Procedures: 64 children aged 5-17 years were classified using the results of standardised language and single-word reading tests into those with no SLI and no RDI (No-SLI/No-RDI) (N = 18), no SLI but with RDI (No-SLI/RDI) (N = 4, not included in analyses because of the small number), SLI/No-RDI (N = 20) and SLI/RDI (N = 22). The groups were compared on a range of tasks engaging different levels of phonological processing (input and output processing and phonological awareness). Outcomes & Results: The SLI/RDI group was distinguished from the SLI/No-RDI and No- SLI/No-RDI groups by more errors in the longer items in nonword repetition and by poorer phonological awareness. Nonword discrimination scores indicated a gradient of performance across groups, which was not associated with a qualitatively different pattern of performance. Conclusions & Implications: This is the first study contrasting input and output processes associated with phonological processing. The results suggest that deficits in SLI plus RDI may be associated with impairment in actively maintaining phonological representations for phonological processing, which is not present in those without RDI and which leads to reading decoding difficulties.