Internal Consistency of the Voice Handicap Index in Individuals With Dysphonia: A Systematic Review and Meta-Analysis.

Objective: To analyze the internal consistency of the Voice Handicap Index (VHI) for evaluating the vocal handicap of individuals with dysphonia.

Methods: This is a systematic review. Studies with a cross-sectional design and including a population of individuals with dysphonia, which validated the VHI and analyzed its internal consistency, were included. The following electronic databases were searched: Cochrane Library, EMBASE, LILACS, and PubMed, including Medline, Scopus, and Web of Science. A manual search was performed in gray literature through the Biblioteca Digital Brasileira de Teses e Dissertações and ProQuest Dissertation & Theses. In addition, the list of references of studies selected in the electronic search was mapped, and an expert in the area was consulted. Two reviewers blindly and independently conducted the selection, data extraction, and analysis of the risk of bias, the certainty of the evidence, and good psychometric measures. A meta-analysis was performed with a random effects model using the JAMOVI 2.3.2 software.

Results: Forty-nine studies were analyzed. In risk of bias assessment, the studies were classified as having inadequate structural validity and very good internal consistency. The analysis of good psychometric properties indicated indeterminate structural validity and insufficient internal consistency. The overall value of Cronbach's alpha was estimated at 0.94, thus suggesting a very good internal consistency. However, there was high heterogeneity. The level of certainty of the evidence was too low for internal consistency.

Conclusion: The VHI proved to be a consistent and reliable patient-reported outcome measure to evaluate voice handicap in individuals with dysphonia; however, studies are heterogeneous, and the certainty of evidence is very low.