Age- and gender-related collagen distribution in human vocal folds

The composition of the lamina propria in human vocal folds has been shown t o affect vocal performance. Collagen plays a significant role in the biomec hanical effects of the lamina propria. Specifically, it lends tensile stren gth to the rapidly oscillating fold. We obtained from a state medical exami ner 38 larynges from men and women in infant, adult, and geriatric age grou ps. We stained the vocal folds for collagen using a picric acid stain and s tudied them using an image analysis system. Distributions of collagen were measured from the superficial to deep layers (from epithelium to vocalis mu scle) within the lamina propria. The data showed an increase in collagen co ntent from infant to adult stages. Infant folds had about 51% of the collag en found in all adults and in geriatric patients (p <.001). There was no si gnificant difference between adult and geriatric folds (p <.16). There was, however, a gender difference in the amount of collagen in both adult surd geriatric specimens. Female adult and geriatric folds had about 59% of the collagen found in male adult and geriatric folds (p <.001). The distributio n pattern of collagen showed that most of the collagen was present in the d eep layer. From these data we conclude that there are age-related and gende r-related differences between male and female infant, adult, and geriatric vocal folds. Stress-strain performance studies need to be correlated with h istologic findings to better study the phonetic implications of these findi ngs.