Application of Regression Discontinuity in Investigating the Effectiveness of Lidcombe Program on Decreasing the Severity of Stuttering in Primary School Children: A Single-Subject Research

Abstract

Background: In single-subject research, there is an autocorrelation between observations, that violates the assumption of observational independence. The regression discontinuity considers the correlation between observations over time and in different treatment stages (baseline, intervention, etc.). The aim of the current study was to compare the visual methods and regression discontinuity method in evaluating the effectiveness of the Lidcombe program on decreasing the severity of stuttering in primary school children of Isfahan City, Iran. Methods: This study with single-subject design was conducted on four children (7-9 years old) who stuttered. Lidcombe program treatment was performed for 22 weeks and its effectiveness on children's speech characteristics was evaluated. Stuttering severity was measured with a rating scale. In order to analyze the data, visual analysis, effect size, and regression discontinuity were used. Findings: Data analysis based on visual analyses as well as regression discontinuity indicated that most participants recorded a significant change as a decrease in severity of syllables stuttered, following the intervention. Regression coefficients in phase change from treatment to follow-up were significant, meaning that the Lidcombe program was effective over time and in phase change from the treatment stage to the follow-up. Conclusion: The results of this study show the positive effect of Lidcombe program on decreasing the severity of stuttering in children and provide the preliminary evidence for the use of this treatment method for the children with stuttering.

Keywords

• stuttering
• speech
• single-case studies as topic
• regression analysis