SLPNarrative ReviewJournal of voice : official journal of the Voice Foundation2025

Vocal Fold Vertical Thickness in Human Voice Production and Control: A Review.

Zhaoyan Zhang

PMID 36964073

WHAT IT FOUND

Vocal fold vertical thickness, not just the gap seen from above, strongly shapes glottal closure and voice quality.

Voice clinicians should consider medial surface shape when assessing voice disorders or planning intervention.

Key findings

01In computer models of voice production, vertical thickness of the vocal fold medial surface had the largest effect on glottal closure, larger than glottal gap, length, stiffness, or subglottal pressure.

02Thin vocal folds can fail to close completely during vibration even when the glottis is closed at rest.

03Small medial surface shape changes in MRI-based models, in the order of 0.5 mm, produced large changes in phonation threshold pressure and closed quotient.

STILL TO COME

How it was doneWhat they foundWhat it means for SLPs

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What it does not show

The main evidence comes from computer models, not from people with voice disorders. The paper is a review of the authors' own simulation work, so independent clinical validation is not provided. Excised larynx and canine experiments cannot show how a live human voice responds to therapy. In humans, thickness, glottal gap and stiffness co-vary, so the paper cannot isolate which control causes a voice change in a patient. The paper does not report patient outcomes, treatment effects or follow-up.

The easy way to misread this

Do not conclude that a therapy that increases vocal fold thickness will improve voice outcomes. The paper reports computational and laboratory findings, not clinical trials in patients.

Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →