Validation of the Communicative Participation Item Bank as an Outcome Measure for Spasmodic Dysphonia

Objectives: Current patient-reported outcome measures do not adequately capture the impact of spasmodic dysphonia (SD) on communication in daily life situations. The aim of this study was to validate the Communicative Participation Item Bank (CPIB), which specifically measures a disease's impact on daily conversational situations, as an outcome measure for SD. Study Design: Multi-institutional prospective cohort study. Methods: A prospective study was conducted with administration of the 46-question CPIB and the Voice Handicap Index-10 (VHI-10) to 190 participants with SD before (time 1) and 6 weeks after (time 2) botulinum toxin injection. Differential item function (DIF) analyses were performed to examine potential item bias. Paired t-tests were used to assess change in each of the CPIB and VHI-10 scores after treatment. Pearson correlations were calculated between the CPIB and VHI-10. Results: DIF analyses revealed no clinically meaningful difference between the item parameters generated for this SD sample and the original CPIB calibration sample. There were statistically significant changes between the pre-treatment and post-treatment time points for both the CPIB and VHI-10. Correlations between the CPIB and VHI were moderate-high. Conclusions: The CPIB item bank, General Short Form, and scoring parameters can be used with people with SD for valid and reliable measurement of the impact of communication disorders on communication in everyday life. The CPIB is sensitive to changes with intervention, proving useful for clinical and research purposes to assess the efficacy and effectiveness of interventions. Level of Evidence: Level 2, prospective observational research with an experimental design (ie, cohort study). Laryngoscope, 131:859–864, 2021.