Diagnostic Value of Acoustic and Aerodynamic Measurements in Vocal Fold Movement Disorders and their Correlation with Laryngeal Electromyography and Voice Handicap Index

Abstract

Objectives: Investigate the relationships between the Voice Handicap Index, laryngeal electromyography, and objective acoustic voice testing in order to determine the utility of these measures in the management of vocal fold movement disorders. Methods: A retrospective review of patients who had completed a Voice Handicap Index-10 (VHI-10) questionnaire, laryngeal electromyography (LEMG), and objective acoustic measurements (including jitter, relative average perturbation, shimmer, noise-to-harmonic ratio, and standard deviation of fundamental frequency). All three tests had been completed within 30 days of the initial evaluation. All patients’ results for acoustic measures were recorded as standard deviations from the norm. LEMG results were converted to grade of paresis (mild, moderate, severe) based on the muscle with the lowest recruitment. Spearman correlation coefficients were calculated to determine the relationship between these three parameters. Results: A total of 313 subjects were included in the analysis. VHI-10, LEMG (grade of paresis), and objective acoustic measures were, at best, weakly correlated. VHI-10 was better correlated than LEMG to each acoustic parameter including the average acoustic scores; however, the highest correlation observed only reached ρ = 0.349 (P < 0.001). The acoustic variables that correlated best with VHI-10 and LEMG were the standard deviation of the fundamental frequency (ρ = 0.349, P < 0.001) and shimmer (ρ = 0.207, P < 0.001), respectively. Conclusion: This study demonstrates that these measures are, at best, weakly associated. VHI-10 correlated better than LEMG (grade of paresis) to each acoustic voice analysis parameter. However, the maximum correlation coefficient observed was 0.349. Therefore, VHI-10 scores and objective voice acoustic measurements are not useful for predicting the severity of vocal fold movement disorders. Moreover, a given severity of paresis can have different effects on voice handicap and acoustic output in different individuals.