Qualitative aspects of developmental language impairment relate to language and literacy outcome in adulthood

Background: Developmental language disorder is a heterogeneous diagnostic category. Little research has compared the long-term outcomes of children with different subtypes of language impairment. Aims: To determine whether the pattern of language impairment in childhood related to language and literacy outcomes in adulthood. Methods & Procedures: Adults who took part in previous studies as children were traced. There were four groups of participants, each with a different childhood diagnosis: specific language impairment (SLI; n = 19, mean age at follow-up = 24;8), pragmatic language impairment (PLI; n = 7, mean age at follow-up = 22;3), autism spectrum disorder (ASD; n = 11; mean age at follow-up = 21;9), and no childhood diagnosis (typical; n = 12; mean age at follow-up = 21;6). Participants were administered a battery of language and literacy tests. Outcomes & Results: Adults with a history of SLI had persisting language impairment as well as considerable literacy difficulties. Pragmatic deficits also appeared to develop over time in these individuals. The PLI group had enduring difficulties with language use, but presented with relatively intact language and literacy skills. Although there were some similarities in the language profile of the PLI and ASD groups, the ASD group was found to have more severe pragmatic deficits and parent-reported linguistic difficulties in conversational speech. Conclusions & Implications: The pattern of deficits observed in different subtypes of developmental language disorder persists into adulthood. The findings highlight the importance of a wide-ranging clinical assessment in childhood, which may provide an indication of outcome in adulthood.