Improving outcomes of preschool language delay in the community: protocol for the Language for Learning randomised controlled trial

Abstract

BackgroundEarly language delay is a high-prevalence condition of concern to parents and professionals. It may result in lifelong deficits not only in language function, but also in social, emotional/behavioural, academic and economic well-being. Such delays can lead to considerable costs to the individual, the family and to society more widely. The Language for Learning trial tests a population-based intervention in 4 year olds with measured language delay, to determine (1) if it improves language and associated outcomes at ages 5 and 6 years and (2) its cost-effectiveness for families and the health care system.Methods/DesignA large-scale randomised trial of a year-long intervention targeting preschoolers with language delay, nested within a well-documented, prospective, population-based cohort of 1464 children in Melbourne, Australia. All children received a 1.25-1.5 hour formal language assessment at their 4th birthday. The 200 children with expressive and/or receptive language scores more than 1.25 standard deviations below the mean were randomised into intervention or ‘usual care’ control arms. The 20-session intervention program comprises 18 one-hour home-based therapeutic sessions in three 6-week blocks, an outcome assessment, and a final feed-back/forward planning session. The therapy utilises a ‘step up-step down’ therapeutic approach depending on the child’s language profile, severity and progress, with standardised, manualised activities covering the four language development domains of: vocabulary and grammar; narrative skills; comprehension monitoring; and phonological awareness/pre-literacy skills. Blinded follow-up assessments at ages 5 and 6 years measure the primary outcome of receptive and expressive language, and secondary outcomes of vocabulary, narrative, and phonological skills.DiscussionA key strength of this robust study is the implementation of a therapeutic framework that provides a standardised yet tailored approach for each child, with a focus on specific language domains known to be associated with later language and literacy. The trial responds to identified evidence gaps, has outcomes of direct relevance to families and the community, includes a well-developed economic analysis, and has the potential to improve long-term consequences of early language delay within a public health framework.Trial registrationCurrent Controlled Trials ISRCTN03981121.

Randomized Trial of a Population-Based, Home-Delivered Intervention for Preschool Language Delay

“…We compared mean outcomes by using linear regression in unadjusted analyses and analyses adjusted for the following prognostic factors: child gender, mother' s education level, recruitment from Let' s Read or Let' s Learn Language, expressive and receptive language scores at baseline, and baseline measure of the outcome being considered when available. In prespecified exploratory analyses, 15 we used tests of interaction to explore whether effects of the intervention on language differ across the following subgroups:…”

“…It was conducted in 8 of the 31 local government areas (LGAs) comprising greater Melbourne, Australia (population 4.0 million in 2011 14 ). Methods are detailed in the published protocol 15 ; Fig 1 summarizes Participants were re-recruited from 2 previous population-based early childhood trials, Let' s Learn Language 10 and Let' s Read, 16 both with robust null findings and over 88% retention at age 3 years. Let' s Learn Language was conducted within 3 LGAs drawn from the lower, middle, and upper socioeconomic tertiles, respectively, as ranked by the Australian censusderived Socioeconomic Indexes For Areas Index of Disadvantage.…”

“…21,22 The program' s development and content are detailed in the trial' s published protocol. 15 Because language delay is clearly not homogeneous by 4 years, we designed a program that is both standardized and replicable, yet flexible enough for children with diverse cognitive and language profiles, 23 unlike the standardized, uniform programs currently the focus of research at younger ages. 24,25 We also aimed for greater intensity and duration than achieved in most clinical services, 26 because the limited literature suggests a doseresponse relationship 27 with both duration 28 and intensity, 29 but it is unclear how consistent these findings are.…”

Two-Year Outcomes of a Population-Based Intervention for Preschool Language Delay: An RCT

“…Intervention Figure 1 summarizes the intervention's timeline and content (for more details, see the trial's published protocol 10 and interim results 15 ). The replicable program was manualized (modeled on that of Boyle 14 ) and sufficiently standardized for population-based delivery by nonspecialists, yet flexible enough to meet the varying needs of children at this age.…”

“…10 Although there is no consensus as to the optimal age for population-based intervention, we chose 4 years because at earlier ages, language delay is both nonspecific and insensitive in predicting later language delay [11][12][13] (ie, low sensitivity), whereas schoolage intervention may be too late. 14 The program was designed to be sufficiently standardized for population-based delivery by nonspecialists, yet flexible enough to meet the varying needs of children at this age.…”