Fidelity measurements in home-based intervention studies for children who stutter

Abstract

Background: Fidelity of Implementation (FOI) refers to the degree to which an intervention is delivered as intended or prescribed. Measuring and tracking FOI in intervention studies is an essential part of ensuring understanding of intervention effectiveness evaluations. Researchers are increasingly utilizing FOI to attain a more holistic comprehension of intervention delivery, aiming to assess whether implementation aligns with intended protocols and correlate this with intervention outcomes. Aims: The overall aim of this thesis was to examine how implementation fidelity influences the effectiveness of an intervention. More specifically, the aims were to: 1) Gain a comprehensive understanding of the reporting of fidelity measurements in previous stuttering intervention research for children who stutter (CWS) where a component of the intervention was implemented in a home environment and to identify gaps in knowledge related to FOI measurements and reporting (Paper I & II, Study I). 2) Examine the effectiveness of a pilot home-based intervention for CWS (stuttering intervention for older children [STOC]) where detailed measurements of implementation fidelity used in the research design (Paper III, Study II). 3) Assess whether high levels of fidelity could be achieved in an intervention study where FOI was incorporated into the design and tightly controlled for during the study (Paper IV, Study III). 4) Determine the relationship between measured FOI and performance on outcome measures for an intervention for school-aged CWS (Paper IV, Study III). Methods: The research was based on a range of methodologies where different methods were applied to answer different research questions. To address Aim 1, a systematic literature search and literature review of published, peer-reviewed papers published between 1981 until 2021 was completed. Thirty-six eligible papers were included and the presence of four key fidelity components in these papers were analysed: dosage, adherence, quality, and responsiveness (Paper II). To address Aim 2, a single case experimental design with multiple baselines was used. STOC intervention consisted of a home-based intervention program combining time-out training with a performance-contingent maintenance schedule strategy. This study was a pilot of the effect of the STOC intervention and involved seven male children aged 9 – 13 who stuttered with children’s stuttering monitored for between 18 to 30 months, depending on the child. Routine monthly speech samples (n=653) and recordings of each intervention session (n=1551) were collected (Paper III) to determine the effect of the viii intervention on children’s speech production. To address Aims 3 and 4, the intervention sessions (n=1551) from Paper III were evaluated based on the four FOI components: dosage, adherence, quality, and responsiveness. FOI was assessed across these dimensions for both parent- and child-managed STOC sessions, each component having specific definitions and methodologies employed for assessment (Paper IV). Results: Within the literature review, no study reported on all four FOI components in both clinical and home settings, and five studies did not report on any FOI component in either setting. The reported number of FOI components ranged from 0 to 4 in clinical settings (M=1.5) and from 0 to 4 in home settings (M=1.0). Dosage was the most frequently reported FOI component (27 studies, 75.0%), while responsiveness was the least frequently reported (16 studies, 44.4%). Despite a slight trend towards increased reporting in recent years, the overall number of FOI components reported did not show a significant increase over time (Paper II). The STOC intervention pilot study demonstrated promising results for all participants, showing reductions in both the frequency and severity of stuttering, along with increases in speech quantity and naturalness. The four participants who completed the intervention reported significant improvements in both their fluency of speech and their quality of life (Paper III). Increased dosage was associated with reduced stuttering, increased speech output, enhanced naturalness, and reduced severity, particularly for sessions managed by the children. Greater adherence was linked to reduced stuttering, more natural speech, and lower severity ratings. However, higher quality and responsiveness were associated with increased speech output but did not correspond to reduced stuttering, enhanced naturalness, or decreased severity (Paper IV). Scores for all four FOI components were higher among participants who completed STOC compared to those who did not, regardless of whether sessions were managed by parents or children (Paper IV). Conclusions: The poor reporting of FOI in intervention research for CWS poses a significant methodological challenge, hindering the ability of clinicians and researchers to interpret study findings accurately. The STOC pilot study revealed improvements in fluency and quality of life for the participants who completed the intervention. Participants who adhered more closely to STOC showed better outcomes; experiencing reduced stuttering. Discrepancies in FOI were apparent when comparing participants who completed the intervention with those who did not. A comprehensive examination of FOI may offer fresh insights into the variability in intervention response in future studies of stuttering interventions. Further research is warranted to delve deeper into the specifics of the STOC protocol. Exploring implementation fidelity could shed light on a significant factor contributing to the variability in intervention outcomes, making it imperative for intervention studies to prioritize thorough measurement and reporting of FOI to advance evidence-based practices