A systematic review of language outcomes in autism spectrum disorder

Background. Language difficulties are common in Autism Spectrum Disorder (ASD). Parents and clinicians need evidence about these outcomes to inform decision-making. Objectives. To systematically review studies reporting... [ view full abstract ]

Background. Language difficulties are common in Autism Spectrum Disorder (ASD). Parents and clinicians need evidence about these outcomes to inform decision-making.

Objectives. To systematically review studies reporting language outcomes in individuals diagnosed with ASD.

Methods. A comprehensive search strategy with a well-established sensitive prognosis filter for Medline, adapted for 5 other database searches, was used. Included studies observed individuals diagnosed with ASD for ≥ 12 months and had ≥ 30 participants. Language outcomes were standardised assessments or notation of the presence/absence of verbal language.

Results. Fifty-six publications (n=5833) met inclusion criteria. Eleven studies had two or more publications. Age at baseline ranged from 17 months to 26 years. Duration of follow-up ranged from 1 to 28 years. Twenty-six studies presented scores from standardised language tools, 11 the presence/absence of verbal language and five both. Most publications (90%) were rated medium to high risk of bias. In all but one study, children with ASD had below average scores at baseline and follow-up. However, most studies (96%) reporting standard scores for a range of language domains found children with ASD progressed at a comparable rate (or better) to typically developing children. The proportion of verbal participants at follow-up ranged from 55% to 94%. Those using phrases at follow-up ranged from 33% to 85%. Meta-analyses were conducted for language domains that contained more than 5 studies.

Conclusion. Most children demonstrated language gain over time. Agreement about language measures and use of best methods for prognosis studies is needed to advance our understanding.

This was a systematic review of studies that have already been published and therefore we did not require ethical approval. The authors have no conflict of interest to declare. [ view full abstract ]

This was a systematic review of studies that have already been published and therefore we did not require ethical approval.
The authors have no conflict of interest to declare.