Influences of aging on taste perception and oral somatic sensation

Background. Many elderly persons report reduced taste perception of the foods they eat. Any disturbance of taste and oral somatic sensations can induce this phenomenon. To determine the cause of decreased taste perception in older persons, the authors investigated age-related changes in taste perception and somatic sensations in the anterior tongue. Methods. Thirty healthy young and elderly persons participated in this study. Recognition thresholds of four basic tastes (sweet, salty, sour, and bitter) and the threshold of irritating sensation induced by capsaicin were measured by local stimulation using filter-paper disks. Two-point discrimination thresholds were measured to evaluate the spatial acuity of touch sensation. All measurements were carried out at the tip of the dorsal tongue. Results. The recognition thresholds of all four basic tastes of elderly participants were significantly higher than those of young participants. On the contrary, age-associated changes were not observed in 2-point discrimination and capsaicin sensation. Conclusions. Significant age-associated deterioration was observed in taste but not somatic sensations such as touch and burning pain in the tongue, showing that aging affects taste perception and oral somatic sensations differently. This suggests that decreased taste perception of foods in elderly people may be caused primarily by perceptual loss of taste among oral sensations.