General Medical Information

Peripheral Nerves

Byron J. Bailey

Changes in peripheral nerves may be important factors in dysphagia, aspiration, and deterioration of vocal quality in the elderly. These systems depend on precise coordination of complex sensory and motor neural systems. We know that several physiologic and morphologic changes account for age-related dysfunction of neural systems in the head and neck. These changes include the general tendency to lose myelinated nerve fibers with increasing age, pathologic changes in Schwann cells, an increase in the cross-sectional area of nerves (caused by an increase in the endoneurial extracellular space), and vascular changes (such as endothelial proliferation and media fibrosis). Altogether, these changes in peripheral nerves appear to parallel the observed deterioration of deglutition, respiration, and vocalization in the elderly.