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Histochemical and morphometrical ageing changes in human vocal cord muscles
M T Rodeño1, J M Sánchez-Fernández, J M Rivera-Pomar
1Department of Pathology, School of Medicine, University of the Basque Country, Bilbao, Spain.
Acta Oto-Laryngologica
|May 1, 1993
Summary
Aging affects vocal cord muscles, leading to changes in fiber type and diameter. Specifically, the thyroarytenoid muscle shows more type I fibers, while the posterior cricoarytenoid muscle shifts towards type II fibers with age.
Area of Science:
- Laryngology
- Histopathology
- Aging Research
Background:
- Vocal cord muscle structure and fiber composition are crucial for voice production.
- Age-related changes in laryngeal tissues can impact vocal function.
Purpose of the Study:
- To investigate the histochemical and morphometrical characteristics of human thyroarytenoid and posterior cricoarytenoid muscles in aging adults.
- To analyze age-related alterations in vocal cord muscle fiber types and diameters.
Main Methods:
- Histochemical and morphometrical analysis of vocal cord muscles from 43 adult human specimens (46-87 years).
- Muscles were sourced from laryngectomy and autopsy cases, excluding those with neuromuscular diseases.
- Statistical regression analysis was employed to identify age-related trends.
Main Results:
- Thyroarytenoid muscle: Type I fibers (44.16%) and Type II fibers (55.84%) showed similar mean diameters. Aging led to a higher percentage of Type I fibers.
- Posterior cricoarytenoid muscle: Type I fibers (66.15%) were more prevalent and larger in diameter than Type II fibers (33.85%). Aging significantly decreased Type I fiber percentage and diameter, increasing Type II fiber variables.
- Age-related thinning of vocal cord mucosa and lamina propria was observed, along with minor changes in connective tissue.
Conclusions:
- Aging significantly alters the fiber type composition and diameter in both thyroarytenoid and posterior cricoarytenoid muscles.
- These age-induced muscular changes, alongside mucosal thinning, likely contribute to age-related vocal dysfunction.