Purpose: This study aimed to examine vocal fold kinematic characteristics associated with typical-frequency and vocal-intensity, high-frequency, and soft-intensity phonation in vocally healthy adults. Method: Glottal area waveform (GAW) was measured from high-speed videoendoscopy in a total of 66 adults (41 women and 25 men) during sustained /i:/ production across the three tasks, resulting in a total of 594 phonations. Statistical analysis of glottal cycle quotients (open quotient OQ, speed quotient SQ, rate quotient RQ, glottal gap index GGI), glottal cycle periodicity (amplitude, time periodicity TP), glottal cycle symmetry (phase asymmetry index, spatial symmetry index, amplitude symmetry index), normalized maximum area declination rate (MADRn), and amplitude-to-length ratio (ALR) was conducted. Principal component analysis was used to identify laryngeal strategies underlying the three tasks. Results: High frequency and soft intensity resulted in changes in SQ, RQ, MADRn, and ALR in female participants, whereas in male participants, they impacted OQ, RQ, GGI, TP, MADRn, and ALR. High-frequency phonation is primarily achieved through increased cricothyroid muscle activity, while soft intensity is primarily achieved by reduced vocal fold adduction and subglottal pressure with compensatory cricothyroid activation. Conclusion: High-frequency and soft-intensity phonations involve distinct laryngeal adjustments and clinically measurable, sex-dependent changes in GAW, highlighting the need to tailor voice therapy to physiological strategies and sex-based differences.
Patel et al. (2026) studied this question.