Patients with multiple sclerosis (MS) may experience taste deficits associated with central nervous system lesions, findings from a study indicate.
Ultimately, some MS patients may lose the ability to distinguish between tastes like sweet, salty, sour, and bitter, as well as experience olfactory dysfunction — both of which can contribute to malnutrition and affect quality of life.
Although most MS patients will retain normal taste function, Richard L. Doty, PhD, of the University of Pennsylvania, and colleagues wanted to explore whether myelin-related lesions correlate with measures of taste function in MS.
The study included 73 patients with MS and 73 matched controls. All participants underwent a 96-trial test of sweet (sucrose), sour (citric acid), bitter (caffeine), and salty (NaCl) taste perception to the left and right anterior and posterior tongue regions. Number and volume of lesions was assessed using quantitative MRI in 52 brain regions of 63 participants with MS.
Compared to controls, taste perceptions in patients with MS were significantly lower for sucrose (P = 0.0002), citric acid (P = 0.0001), caffeine (P = 0.0372) and NaCl (P = 0.0004), with deficits present in both the anterior and posterior tongue regions. The percentage of MS patients with scores falling below the 5th percentile of controls was 15.07% for caffeine, 21.9% for citric acid, 24.66% for sucrose, and 31.50% for NaCl, suggesting that taste dysfunction, albeit less noticeable, is a common feature of MS.
Taste scores were found to be inversely correlated with lesion volumes in the temporal, medial frontal, and superior frontal lobes, and with the number of lesions in the left and right superior frontal lobes, right anterior cingulated gyrus, and left parietal operculum.
The study authors note that brain structures typically associated with taste showed no or few MS-related lesions, suggesting that taste dysfunction in MS may be associated with other, higher brain structures.
While further studies are necessary to confirm this association, the authors point out that physicians don’t typically evaluate MS patients for deficits in taste or smell, and that doing so may help identify patients who may benefit from nutritional counseling or other therapies.