Examining the Effect of Volitionally Altering Fundamental Frequency on Measures Associated With Vocal Hyperfunction.

Area of Science:

• Speech-language pathology
• Acoustic phonetics
• Voice science

Background:

• Speech-language pathologists (SLPs) aim to support gender-congruent voice use in transgender and nonbinary individuals.
• A key concern is the potential for developing vocal hyperfunction (VH) during pitch modification.

Purpose of the Study:

• To investigate the effects of volitionally altering fundamental frequency (f_o) on measures associated with vocal hyperfunction (VH).
• To compare vocal changes in males and females when altering f_o in gender-typical directions.

Main Methods:

• Forty participants (20 female, 20 male) without vocal complaints altered their habitual f_o by two semitones.
• Acoustic, aerodynamic, videostroboscopic, and perceptual measures were assessed under habitual and altered f_o conditions.
• Analysis focused on the interaction between sex and f_o condition.

Main Results:

• Seven of 13 measures were significantly affected by the sex and f_o condition interaction.
• Altered f_o vocalizations were generally more consistent with VH than habitual f_o vocalizations.
• Females lowering f_o showed increased vocal tract length and higher smoothed cepstral peak prominences (CPPS) and low-to-high (L/H) ratios; males raising f_o showed shorter vocal tract lengths and lower L/H ratios.

Conclusions:

• Volitionally altering fundamental frequency (f_o) can induce physiological changes associated with vocal hyperfunction (VH).
• Females exhibited more significant vocal measure changes than males when altering f_o, contrary to expectations.
• These findings highlight the physiological adjustments necessary for pitch modification and potential VH risks.