A Framework for Measuring Treatment Fidelity in Motor-Based Speech Intervention for Children With Childhood Apraxia of Speech

Examining adherence to a treatment protocol is a critical component of intervention research. This is particularly challenging in treatment involving young children with childhood apraxia of speech (CAS) where treatment is provided in a dynamic manner. The purpose of this work was to first present a framework for measuring fidelity of Dynamic Temporal and Tactile Cueing (DTTC), a motor-based treatment designed for children with CAS. This framework includes the DTTC Fidelity Checklist and a collaborative review process between investigators and treating speech-language pathologists (SLPs). We then quantify the fidelity of SLPs trained to administer DTTC to young children with CAS. Three SLPs provided 8 weeks of intervention to 19 children with CAS (ages 2;9-6;7 [years;months]). Two investigators and the SLPs independently rated fidelity at multiple time points across the intervention period. Regression analyses were used to estimate the change in fidelity over time and across specific categories of the DTTC Fidelity Checklist. Reliability between the investigators and SLPs was examined using an adjusted Spearman correlation. SLPs demonstrated high levels of adherence to the DTTC protocol. Ratings were found to be lower for one category of the DTTC Fidelity Checklist related to providing the child movement-based cues and giving explicit instructions to feel speech movements. Investigator and SLP ratings were highly consistent with one another, and correlations were very strong across all categories. This study presented a framework for measuring treatment fidelity during DTTC. Strong interrater reliability between investigator and SLP ratings supports the DTTC Fidelity Checklist as an evidence-based tool, providing a foundation for improving the precision of DTTC implementation in clinical and research settings.