SLPRCTJournal of voice : official journal of the Voice Foundation2025

Efficacy of a Tesla Valve Straw in a Semi-Occluded Vocal Tract Exercise in a Normal-Voiced Population.

Owen P Wischhoff, Jakob R Holm, Sathviga Sri Ravi Shankar and 2 others

PMID 40246614

WHAT IT FOUND

Straw phonation reduced phonation threshold pressure in healthy adults, making voice production easier.

However, a novel Tesla valve straw was no more effective than a standard straw. The benefit came from the semi-occlusion itself, not the specific straw design or length.

Key findings

01Phonation threshold pressure significantly decreased after straw phonation exercises across all conditions, indicating reduced effort to start voicing.

02There was no significant difference in phonation threshold pressure reduction between the standard straw and the Tesla valve straw.

03Mean flow rate and fundamental frequency did not change significantly after the exercises.

STILL TO COME

How it was doneWhat they foundWhat it means for SLPs

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What it does not show

The study was conducted on a normal-voiced population, so results may not generalize to patients with voice disorders. Only two straw lengths were tested, with a small difference of 6.00 cm between them, which may have been too subtle to detect length effects. The Tesla valve design used was just one specific geometry; other configurations might behave differently. The study did not measure supraglottic pressure directly during the exercises, relying instead on PTP as a proxy.

Declared interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

The easy way to misread this

Do not assume the Tesla valve straw is superior because it has higher resistance. While bench tests showed it creates more pressure, this did not lead to better vocal efficiency outcomes in humans compared to a standard straw.

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