Age-Related Decline in Arytenoid Sensory Innervation May Be Contributing Factor to Presbyphagia

by Linda Kossoff •

How does healthy human laryngopharyngeal sensory innervation density correlate with age?

BOTTOM LINE

Study findings document age-related decline in arytenoid innervation and in myelinated, putative mechanosensory innervation density, which may be a contributing factor to presbyphagia.

BACKGROUND: Swallowing dysfunction is common in naturally aging but otherwise healthy adults; however, little is known about the identities of sensory neurons that coordinate human swallowing and whether they are modified with age. Understanding sensory substrates of swallowing has the potential to inform the development of novel treatments for dysphagia.

STUDY DESIGN: Prospective study.

SETTING: Department of Otolaryngology–Head and Neck Surgery, Columbia University, New York, N.Y.

SYNOPSIS: Researchers recruited 25 adult volunteers without clinical diagnosis of dysphagia or clinical indication for biopsy. Participants underwent biopsies from the tongue base, lateral and midline pharyngeal wall, epiglottis, and arytenoids. Tissue sections were labeled with antibodies for all neurons, myelinated neurons, and chemosensory cells. Densities of lamina propria innervation, epithelial innervation, solitary chemosensory cells, and taste buds were calculated and correlated with age. Results showed the epiglottis and arytenoid densely innervated with intraepithelial nerve fibers, suggesting these sites can transduce a rich array of chemical, thermal, and mechanosensory stimuli. Arytenoids showed the highest density of innervation and chemosensory cells across all measures and were the only site found to have significant changes in innervation across the lifespan. Tongue base, lateral pharynx, and midline posterior pharynx had minimal innervation and few chemosensory cells, and significant change in innervation densities across age. Epithelial innervation was present primarily near chemosensory cells and taste buds. Overall innervation and myelinated fibers in the arytenoid lamina propria were shown to decline with aging. Study limitations included lack of detailed medical history on subjects in the data analysis.

CITATION: Cole CL, Yu VX, Perry S, et al. Healthy human laryngopharyngeal sensory innervation density correlates with age. Laryngoscope. 2023;133:773-784.