Influence of smell loss on taste function.

The influence of damage to one sensory system on the functioning of other sensory systems has been of scientific interest for over a century. Recently it has been suggested that damage to the olfactory system (CN I) decreases the ability to taste; that is, to perceive sweet, sour, bitter and salty sensations via CN VII, IX, and X. If true, this would be in contrast to most other sensory systems, where compromise typically leads to either cross-modal enhancement of function or to no effects at all. In the present study, data from both regional and whole-mouth taste tests of 581 patients presenting to a smell and taste center with varying degrees of olfactory function were evaluated to address whether olfactory loss is associated with taste loss. No significant influence of olfactory dysfunction on any measure of taste perception was found when the effects of sex, age, and etiology were controlled. These data suggest that smell loss, per se, has no meaningful influence on taste function, and that clinical associations between smell and taste dysfunction, when observed, likely reflect comorbid influences.