A randomized study of parent- versus child-directed intervention for Dutch toddlers with DLD

Indirect speech and language therapy, such as parent-implemented intervention, has been shown to be an effective approach for young children with speech and language disorders. However, relatively few studies have compared outcomes of parent-directed therapy with child-directed intervention, that is, individual therapy of a child delivered by a speech and language therapist (SLT). Although speech and language therapists (SLTs) regard parental engagement as imperative for successful intervention, currently they predominantly use child-directed intervention.

To evaluate the effect of parent- versus child-directed speech-language therapy embedded in usual care intervention for young children with developmental language disorder (DLD).

In a randomized trial, forty-six 3-year-old monolingual children with DLD were assigned to parent-directed intervention or child-directed intervention groups. In addition, all children received usual care in special-language daycare centres. Outcomes included children's language development and functional communication, parents' language output, parents' perceptions and their self-efficacy. These were assessed at three time intervals, that is, at baseline, immediately after 6 months of treatment, and 1 year after baseline. The parent-directed intervention consisted of twelve 50-min sessions every 2 weeks with parent and child, consisting of parental training with immediate feedback by (SLTs. Children in the child-directed intervention group received individual speech-language therapy in weekly 30-min sessions for 6 months.

Intervention in both groups was equally effective. All children improved significantly in receptive and expressive language measures as well as in functional communication at all intervals. All parents used significantly more language support strategies and were less concerned about their child's participation in communication. Parents in the parent-directed intervention group reported increased self-efficacy in stimulating their child's language development. In contrast, parents in the child-directed intervention group reported a decrease in self-efficacy. Though modest, these group differences were significant in both the short and long terms. Both parents and SLTs were positive about the parent-directed intervention.

The effects of parent- and child-directed intervention for young children with DLD are similar. The parent-directed intervention adds to treatment options for parents as well as for SLTs and creates choices for shared decision-making.

What is already known on the subject Language therapy for young children with DLD comprises various delivery models. Two of these are child- and parent-directed therapy by SLTs. Compared with no treatment, both delivery models are effective, but it is unclear if one of these results in better language outcomes than the other. SLTs value child-directed intervention more highly than indirect approaches where treatment is delivered by others. This study aims to compare the relative effectiveness of parent-directed intervention with child-directed intervention, both parts of multi-component usual care intervention. What this paper adds to existing knowledge This randomized trial indicates that a parent-directed intervention model is as effective as child-directed intervention by SLTs for children's language development and functional communication. Parents' use of language support strategies was also similar in both intervention models, in the short and long terms. Like in child-directed therapy, parent-directed intervention reduces parents' concerns. Contrary to child-directed treatment, parent-directed intervention increases parents' self-efficacy, that is, supporting their child's language development. What are the potential or actual clinical implications of this work? Though SLTs predominantly choose a child-directed intervention model, the study results show that they can consider parent-directed approaches too. There are no significant differences in children's language outcomes as a function of parent- or child-directed intervention. Furthermore, parents and SLTs were positive about the parent-directed intervention program and the SLTs evaluated it as valuable and feasible.