Volitional Control of Frequency and Intensity in Speakers With and Without Hyperfunctional Voice Disorders.

Purpose: Prior studies of vocal auditory-motor control in people with hyperfunctional voice disorders (HVDs) have found evidence of unusually large responses to auditory feedback perturbations of fundamental frequency (0) and more variable voice onset times in unperturbed speech. However, it is unknown whether people with HVDs perform similarly to people with typical voices when asked to make small changes in vocal parameters in volitional tasks. The purpose of this study was to compare performance on minimal movement tasks for 0 and intensity in people with and without HVDs.

Method: Twenty-six people with HVDs and 26 matched controls participated in tasks to assess the smallest volitional increases and decreases they could make in vocal 0 and intensity. Measures included the mean smallest change, variability of change, and accuracy of the direction of change. Group differences were tested with general linear models.

Results: No significant differences were found between people with and without HVDs on any of the measures. Singers produced significantly smaller mean smallest changes of both 0 and intensity than nonsingers.

Conclusions: Our findings support the interpretation of prior studies of auditory-motor control in people with HVDs. Specifically, unusually large responses to perturbations of vocal auditory feedback cannot be explained by a broader impairment of the ability to make small changes in the vocal parameters 0 or intensity. The method devised to assess minimal movements for voice is sensitive to relevant group differences, such as singing experience.

Supplemental Material: https://doi.org/10.23641/asha.30004969.