Is speech and language therapy effective at improving the communication of adults with intellectual disabilities?: A systematic review

Abstract

Background A significant proportion of adults with intellectual disabilities (ID) experience speech, language and communication difficulties which are associated with poor physical and mental health outcomes. Speech and language therapy (SLT) interventions are an important way to address these communication difficulties, yet there is limited available evidence to provide information about the effectiveness of the different approaches used for this heterogeneous group. Aims To review the evidence available for the effectiveness of SLT interventions aimed at improving communication for adults with ID. Methods & Procedures A systematic search across relevant databases was performed. Information on methodological details of each relevant study, along with descriptions of the SLT interventions employed, were extracted and the Crowe Critical Appraisal Tool (CCAT) was used to assess quality. Findings were discussed in a narrative synthesis grouped by target communication skill. Outcomes & Results A total of 10 relevant studies met the inclusion criteria. These were predominantly interventions aimed directly at adults with ID to improve speech, increase augmentative and alternative communication (AAC) use and develop interaction skills, with one study addressing work with carers. The included studies were all rated as low quality. There is weak preliminary evidence that SLT input can improve the communication skills of adults with ID. Conclusions & Implications There is insufficient evidence to draw strong conclusions about the effectiveness of SLT in this population. Further high-level evidence across speech, language and communication domains is urgently needed. What this paper adds What this paper adds to existing knowledgeWhat is already known on the subject What are the potential or actual clinical implications of this work? There is limited evidence for community health interventions used with adults with ID. Previous reviews of SLT interventions found a lack of evidence base for this population. Some areas of SLT practice such as AAC have demonstrated potential benefits and other areas including speech work, social communication skills and training for communication partners have some evidence base for children with ID but there is currently insufficient evidence for adults with ID. The study systematically reviews the current evidence base available when considering the effectiveness of SLT intervention for adults with ID. It provides weak evidence to suggest SLT intervention can improve communication in this population and highlights the need for clinically relevant, robustly designed studies to be undertaken in this field. The lack of high-quality studies with sufficient power to draw conclusions about effectiveness means SLTs are not able to base their intervention choices on firm evidence. There is an urgent need to conduct robust research into the effectiveness of SLT interventions for adults with ID.