Characterization of Vocal Motor Control Using Laryngeal Kinematics in Individuals With Hyperfunctional Voice Disorders.

Purpose: High-speed videoendoscopy was used to investigate how underlying laryngeal motor control strategies differ in individuals with and without hyperfunctional voice disorders (HVDs). Three laryngeal kinematic measures were defined to characterize laryngeal motor control: kinematic stiffness, spatiotemporal index, and asymmetry index. Method: Twenty-eight adults with HVDs and 28 age- and sex-matched controls produced repeated utterances of /ifi/ at three different gesture rates (50, 65, and 80 beats per minute) and three self-induced vocal effort levels (mild, moderate, and maximum effort) to elicit a range of linguistic contexts for the vocal targets produced. The glottal angle profiles of /ifi/ productions were extracted to calculate three kinematic measures of laryngeal motor control: kinematic stiffness (estimating laryngeal muscle tension), spatiotemporal index (estimating production variability), and asymmetry index (estimating movement asymmetry). Results: Individuals with HVDs exhibited statistically significantly higher kinematic stiffness during varying effort levels and higher spatiotemporal indices and asymmetry indices compared to controls, indicating higher laryngeal muscle tension, production variability, and movement asymmetry, respectively. Conclusion: Laryngeal kinematics suggest differing underlying motor control strategies in individuals with HVD relative to controls, which may inform better understanding of the etiology of HVDs. Supplemental Material: https://doi.org/10.23641/asha.28550387 [ABSTRACT FROM AUTHOR]