Characteristics of Phonatory Function in Singers and Nonsingers With Vocal Fold Nodules

Purpose. The goals of this study were to determine if there were significant differences between singers and nonsingers in the morphology of vocal nodules and the associated impact on vocal function. Method. Participants were 10 professionally trained singers with nodules, eight nonsingers with nodules, and 10 individuals with healthy normal voice (controls). Surface electromyography (sEMG) from three anterior neck locations and acoustic rise times for vowels /a/ and /i/ were measured in all the participants. In individuals with nodules, dB SPL/cm H2O, glottal airflow, and nodule location and size were also measured. Results. There were no significant differences between singers and nonsingers with nodules in terms of airflow, dB SPL/cm H2O, nodule size, or nodule location. In nonsingers with nodules, airflow and nodule size were significantly correlated, but were not significantly correlated in singers. Vowel rise times and sEMG during vocal tasks did not differentiate among nodule and control groups. Sternocleidomastoid sEMG during initiation of the vowel /a/ was statistically significantly stronger in nonsingers with nodules relative to singers with nodules and controls. Conclusions. Nodule morphology did not differ between singers and nonsingers, although some behavioral aspects of phonation differed between the groups.