Service delivery and intervention intensity for phonology-based speech sound disorders

When planning evidence-based intervention services for children with phonology-based speech sound disorders (SSD), speech and language therapists (SLTs) need to integrate research evidence regarding service delivery and intervention intensity within their clinical practice. However, relatively little is known about the optimal intensity of phonological interventions and whether SLTs' services align with the research evidence.

The aims are twofold. First, to review external evidence (i.e., empirical research evidence external to day-to-day clinical practice) regarding service delivery and intervention intensity for phonological interventions. Second, to investigate SLTs' clinical practice with children with phonology-based SSD in Australia, focusing on service delivery and intensity. By considering these complementary sources of evidence, SLTs and researchers will be better placed to understand the state of the external evidence regarding the delivery of phonological interventions and appreciate the challenges facing SLTs in providing evidence-based services.

Two studies are presented. The first is a review of phonological intervention research published between 1979 and 2016. Details regarding service delivery and intervention intensity were extracted from the 199 papers that met inclusion criteria identified through a systematic search. The second study was an online survey of 288 SLTs working in Australia, focused on the service delivery and intensity of intervention provided in clinical practice.

There is a gap between the external evidence regarding service delivery and intervention intensity and the internal evidence from clinical practice. Most published intervention research has reported to provide intervention two to three times per week in individual sessions delivered by an SLT in a university clinic, in sessions lasting 30-60 min comprising 100 production trials. SLTs reported providing services at intensities below that found in the literature. Further, they reported workplace, client and clinician factors that influenced the intensity of intervention they were able to provide to children with phonology-based SSD.

Insufficient detail in the reporting of intervention intensity within published research coupled with service delivery constraints may affect the implementation of empirical evidence into everyday clinical practice. Research investigating innovative solutions to service delivery challenges is needed to provide SLTs with evidence that is relevant and feasible for clinical practice.