The Effect of Water Resistance Therapy on the Impulse Dispersion of Aerosols During Sustained Phonation.
Marie Christine Köberlein, Laila Hermann, Sophia Gantner and 7 others
PMID 35803772WHAT IT FOUND
A water-submerged tube used in voice therapy produced smaller aerosol clouds in front but wider sideways and upward spread than usual singing.
Safety distances may still be needed in all directions.
Key findings
01At the end of phonation, the aerosol cloud reached 0.88 m to the front and had a 1.05 m side-to-side diameter.
02Compared with usual singing, the exercise showed lower front distances but higher lateral and upward distances.
03Safety distances would still be required in all directions because lateral expansion might be larger than usual singing.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study measured aerosol dispersion in 12 professional singers, and one singer was omitted from the results. The aerosols were generated with e-cigarette base liquid, so they may not represent the concentration of virus-laden particles in real exhalation. The experiment measured one sustained phrase, so it cannot predict aerosol accumulation during longer singing or with several people at once. The comparisons with usual singing and a vocalize task came from earlier recordings, and the tasks had different pitch content. The study did not test whether aerosols remained in the water inside the bottle. The study did not represent convectional flows in non-laboratory settings. The study tested only LAX VOX, not other semi-occluded vocal tract exercises such as straw phonation, humming, lip trills, tongue trills, consonants, or a hand over the mouth.
Declared interests
The authors declared no competing interest.
The easy way to misread this
Do not conclude that a water-submerged tube makes singing safe without distancing. It lowered the front distance, but clouds spread more sideways and upward, and the study did not measure infection risk.