Medial Surface Dynamics as a Function of Subglottal Pressure in a Canine Larynx Model.
Liran Oren, Sid Khosla, Ephraim Gutmark
PMID 31387765WHAT IT FOUND
In excised dog larynges, the timing difference between the top and bottom of the vocal folds changes with air pressure, contradicting fixed clinical assumptions.
Current video methods miss the top fold's movement during closing, limiting how we understand voice production mechanics.
Key findings
01The phase lag between the superior and inferior edges of the vocal fold varies with subglottal pressure, rather than being constant.
02High-speed video captures the inferior fold dynamics during closing, but fails to capture the superior fold's movement, which has a higher rate of change.
03Glottal area waveform skewing occurs without a vocal tract, suggesting intraglottal vortices (not just vocal tract resonance) drive closing mechanics.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study used excised animal larynges without a vocal tract, so the findings may not apply to living human phonation where vocal tract resonance plays a major role. The sample size was very small (four larynges). The mechanism proposed (vortices) is theoretical and cannot be directly measured in a clinical setting.
Declared interests
The authors declared no financial or personal interests. The study was approved by the University of Cincinnati's Animal Care and Use Committee.
The easy way to misread this
Do not assume these findings directly change how you interpret a patient's stroboscopy or voice quality. The study describes mechanical principles in an excised animal model without a vocal tract, which limits its direct application to diagnosing or treating human voice disorders.