Speech and language delays in preschool childrenBMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d5181 (Published 25 August 2011) Cite this as: BMJ 2011;343:d5181
- James Boyle, professor of psychology
Speech and language delays affect 6-7% of children at school entry and can result in problems in one or more areas, such as understanding vocabulary and grammar, inferring meaning, expressive language, sound production, voice, fluency and articulation, and the use of language in social contexts.1 For some children, language problems are markers for—and secondary to—conditions such as autism, sensory impairment, or more general developmental disabilities. For others, they are the result of primary delay that cannot be accounted for by low non-verbal ability, hearing impairment, behaviour problems, emotional problems, or neurological impairments. Environmental factors such as limited opportunities for learning language or learning English as an additional language may also overlap with primary and secondary delay. In the linked cluster randomised trial (doi:10.1136/bmj.d4741), Wake and colleagues assess the effects of a low intensity parent-toddler language promotion programme delivered to toddlers identified as slow to talk on screening in universal services.2
Language delay that persists until school entry can have adverse effects on literacy, behaviour, social development, and mental health into adulthood, with receptive language and secondary delay particular risk factors.3 4 5 6 But the case for secondary prevention—the early identification of language delay and early intervention before specialist investigation—is not clear cut. Firstly, variability in language development makes it difficult to identify delay early. For example, 50-60% of untreated 2 year old children who present with primary expressive language delay may be expected to “catch up” with their typically developing peers over the ensuing 12 months.7 Secondly, although systematic reviews show that interventions can have a short term positive effect on language delay in young preschool children relative to untreated controls—particularly for difficulties in phonology, expressive vocabulary, and auditory comprehension—only a few large scale studies have been reported.8 9
Wake and colleagues’ study conducted in Australia is thus of particular interest.2 The study was a cluster randomised controlled trial of a community based programme to promote the language skills of young children who are slow to talk. Children who scored below the 20th centile at 18 months on a standardised parent reported checklist of expressive language were randomised to an intervention group (n=158) or to a usual care control group (n=143). The intervention comprised six two hour group based training sessions for parents, which included coaching using videotapes of the parent and child to encourage effective child centred interaction over a six week period. The study found no significant differences between groups in parent reported measures of expressive language and behaviour or blinded assessment of expressive and receptive language by professionals using standardised tests at 2 years and 3 years of age.
Despite these results, the study provides insight into the feasibility of a secondary prevention programme for language disorders. This large scale population based study cost $A895 (£568; €645; $917) per family, targeted parents who were worried about their children’s language development, and included children who were learning English as an additional language.
Although parents randomised to the intervention reported that they found the programme both “acceptable” and “feasible” in terms of its implementation, 43% attended fewer than half of the available sessions and only 57% attended four or more sessions. Furthermore, it was evident from the mean standard scores for expressive and receptive language at 3 years that many of the participants randomised to the control group who presented with expressive vocabulary delay at 18 months had caught up with their typically developing peers at 3 years.
The authors identify the limitations of the study. The children may have been too young to identify language delay accurately, given the wide developmental trajectories at 18 months and the sensitivity and specificity of the language measures available. The low intensity and duration of the six week intervention as well as variable levels of parental engagement might also have contributed to the lack of effect.
In terms of the implications for practice, the study highlights the importance of well designed clinical trials to inform the best use of resources. It is also clear that the early and reliable identification of language delay under 2 years of age is problematic in all but the most severe cases. A population based approach may therefore not be the most effective way to proceed. General practitioners, health visitors, and professionals involved in the early years should ensure that information about typical child development and milestones is readily available to parents. This can provide a basis for eliciting parents’ concerns about their children’s speech and language and for providing advice and support. In the United Kingdom, websites of charities such as Afasic (www.afasic.org.uk), I CAN (www.ican.org.uk), and the National Literacy Trust (www.literacytrust.org.uk) provide helpful guidance for parents about language development and how to encourage it. Referral by the general practitioner for specialist speech and language advice or triage assessment would be warranted if the problems are severe, perhaps involving not only sound production or expressive language but also marked difficulties in comprehension, social communication, and social interaction. Developmental checklists and other diagnostic tests could be used by general practitioners and health visitors to clarify the nature and severity of problems to inform decisions about whether to refer on or monitor the child’s progress.10 11
Future research should include well designed controlled studies with economic evaluation to assess the most effective intensity and duration of intervention programmes for speech and language delay in the early years, particularly those involving parental engagement. In parallel, observational studies could further assess the effects of risk factors including receptive delay and learning English as an additional language.
Cite this as: BMJ 2011;343:d5181
Competing interests: The author has completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Provenance and peer review: Commissioned; not externally peer reviewed.