Pre-adolescent children exhibit lower aerosol particle volume emissions than adults for breathing, speaking, singing and shouting.

Speaking and singing are activities linked to increased aerosol particle emissions from the respiratory system, dependent on the utilized vocal intensity. As a result, these activities have experienced considerable restrictions in enclosed spaces since the onset of the COVID-19 pandemic due to the risk of infection from the SARS-CoV-2 virus, transmitted by virus-carrying aerosols. These constraints have affected public education and extracurricular activities for children as well, from in-person music instruction to children's choirs. However, existing risk assessments for children have been based on emission measurements of adults. To address this, we measured the particle emission rates of 15 pre-adolescent children, all eight to ten years old, with a laser particle counter for the test conditions: breathing at rest, speaking, singing and shouting. Compared with values taken from 15 adults, emission rates for breathing, speaking and singing were significantly lower for children. Particle emission rates were reduced by a factor of 4.3 across all conditions, whereas emitted particle volume rates were reduced by a factor of 4.8. These data can supplement SARS-CoV-2 risk management scenarios for various school and extracurricular settings.

Oscillatory Onset and Offset in Young Vocally Healthy Adults Across Various Measurement Methods.

OBJECTIVE: This study aimed to investigate the relationship between (1) oscillatory onset-offset time across various approaches that use different measurement criteria and (2) oscillatory onset and offset times in vocally healthy young adults. METHOD: Oscillatory onset-offset times were obtained from 71 vocally normal adults, using high-speed videoendoscopy. Comparisons between the different onset methods involved measurement of the oscillatory onset time (OOT), voice initiation period (VIP), and the phonation onset time (POT), and for offset methods involved computation of the oscillatory offset time (OOToff) and the phonation offset time. RESULTS: Correlation of the OOT with the VIP was 0.240 (P = 0.04) and with the POT form glottal area waveform was 0.248 (P = 0.04); however, correlation between the VIP and the POT glottal area waveform was 0.661 (P < 0.001). For offset, there was a moderate correlation (rS = 0.503, P < 0.001) across OOToff and vocal offset period. The onset time was longest for the OOT followed by the VIP and the POT. There was no correlation between onset and offset for all methods. CONCLUSIONS: A framework for quantification of oscillatory onset-offset time was developed for /hi/ tasks, which can be used for future measurements of disordered voice. A positive relationship was observed between VIP and POT and between OOToff and vocal offset period. There was a nonlinear relationship between the OOT, VIP, and POT measures. Onset-offset times are strongly influenced by the calculation method used, the pros and cons of which are discussed in this paper. Vibratory onset and offset represent physiologically different phenomena.

Spatiotemporal Quantification of Vocal Fold Vibration After Exposure to Superficial Laryngeal Dehydration: A Preliminary Study.

OBJECTIVES: The aim of the study was to evaluate the effects of a superficial laryngeal dehydration challenge on vocal fold vibration in young healthy adults using high-speed video imaging. SUBJECTS AND METHODS: In this prospective study, the effects of a 60-minute superficial laryngeal dehydration challenge on spatial (speed quotient, amplitude quotient) and temporal measures (jitter percentage, vibratory onset time) of vocal fold vibration and phonation threshold pressure (PTP) were evaluated in 10 (male = 4, female = 6) vocally normal adults (21-29 years). All measures except the vibratory onset time were measured at the 10 (low) and 80 (high) percent level of their pitch range. The vibratory onset time was obtained at habitual pitch and loudness level. Superficial laryngeal dehydration was induced by oral breathing in low ambient humidity. Prechallenge and postchallenge differences were statistically investigated using t tests with Bonferroni correction. RESULTS: The speed quotient at low-pitch phonation significantly decreased after oral breathing of low ambient humidity. Other spatiotemporal measures and PTP at low and high pitch were not significant after challenge. CONCLUSIONS: Results from this initial study have implications for the use of high-speed video imaging to detect and quantify the subtle changes in vocal fold vibrations after superficial dehydration in healthy individuals. Preliminary findings indicate that superficial dehydration in healthy individuals results in spatial deviations at low pitch. However, further studies are warranted to identify additional spatiotemporal changes in vocal fold vibration after superficial dehydration in normal and disordered populations.