Age-related changes of elastic fibers in the superficial layer of the lamina propria of vocal folds.

An investigation was carried out to determine the morphologic characteristics of elastic fibers in the superficial layer of the lamina propria of aged vocal folds (EFAVFs). Excised human adult vocal folds served as the material for this study. Scanning and transmission electron microscopic observations were made. The results can be summarized as follows. First, the EFAVFs were composed of amorphous substances and microfibrils. The amorphous substances increased in amount and the microfibrils became less numerous. Second, the EFAVFs ran in various directions, were branched, and formed a complicated network. The surface of the fibers was rough, and the fibers appeared to vary in size. Some EFAVFs united to form a sheet with a rough surface. Third, the EFAVFs could not be easily digested by elastase compared with those of younger adults. We conclude that the morphologic and metabolic changes of elastic fibers in the most important vibrating portion (superficial layer of the lamina propria) of the aged vocal folds contribute partially to aging of the voice.