AGE-RELATED AND GENDER-RELATED ELASTIN DISTRIBUTION CHANGES IN HUMAN VOCAL FOLDS

The composition of the lamina propria in human vocal folds has been sh own to affect vocal performance. Elastin plays a significant role in t he biomechanical effects of the lamina propria, We obtained 19 larynge s from the state medical examiner from subjects whose cause of death w as unrelated to the trachea and laryngeal regions. The sample containe d male and female subjects in the infant, adult, and geriatric age gro ups, We stained the vocal folds for elastin with Verhoeff's elastic ti ssue stain and studied them with use of an image analysis system confi gured for light microscopy. Distributions of elastin were measured fro m superficial to deep within the lamina propria (from epithelium to vo cal muscle). These elastin distributions were then compared with the u se of statistical software. The data showed that there was an increase in elastin content from the infant through geriatric stages. No gende r-related differences were found. Infant folds had about 23% of the el astin found in adults, and geriatric subjects had about 879% of the el astin found in adults. Both of these results were statistically signif icant (p < 0.05). The distributions were consistent with previous obse rvations that the lamina propria is a layered structure with most of t he elastin present in the intermediate layer. This layer was larger in geriatric subjects than in adult and pediatric subjects. We observed that the fiber diameter appeared to be larger in geriatric subjects (t his observation is currently being verified with electron microscopy) whereas smaller, spiraled fibers appeared in pediatric subjects.