OBJECTIVE: To determine the influences of multiple sclerosis (MS) on the frequency, nature, and magnitude of gustatory deficits to sucrose (sweet), citric acid (sour), caffeine (bitter) and sodium chloride (salty) for anterior and posterior sectors of the tongue. To establish whether taste test scores are correlated with lesion activity within specific brain regions. BACKGROUND: Although numerous studies have assessed taste function in multiple sclerosis, findings have been variable and prevalence rates as low as 1% have been reported. To date, most empirical studies have evaluated small samples and none have tested anterior (CN VII) and posterior (CN IX) tongue regions separately. Moreover, correlations between taste test scores and MRI-determined lesion activity within the brain have not been evaluated. DESIGN/METHODS: Case control study. Seventy three MSpatients and 73 age-, sex- and race-matched controls were tested. Correlations were computed between the test measures and the number and volume of multiple-sclerosis-related lesions in the frontal lobe, temporal lobe, brain stem, thalamus, and cerebellum. RESULTS: Overall, 21.92% of the MS patients exhibited taste test scores below the 5th percentile of controls, with NaCl contributing the most to this effect (respective NaCl, citric acid, sucrose & caffeine percentages = 21.91%, 16.4%, 11.0% and 8.2%; Cochran’s Q test P = 0.016). Negative correlations were noted between sucrose identification scores and lesion volumes in the right temporal lobe, and between citric acid identification scores and lesion volumes in both temporal lobes. CONCLUSIONS: MS was associated with taste dysfunction on both the front and back of the tongue in about one-fifth of the patients. Lesion activity, in some brain regions, was correlated with the magnitude of the deficits for some taste stimuli. Importantly, all classical taste qualities are affected, with a slightly greater influence on tastants that employ transduction mechanisms that directly gate membrane channel receptors. Study Supported by: NIH RO1 DC 02974, NIH R01 NS 37172, and DOD W81XWH-09-1-0467. Disclosure: Dr. Doty has received personal compensation for activities with Sensonics, Inc. Adams & Adams, Christopher Abdoney, Clancy & Stevens, Columbia University, Federal Defenders, Middle Dist. Alabama, Lathrop & Gage LLP, Merck, Murphy-Brown LLC, National Institutes of Health, Rothshild Wishek & Sands LLP, Pfizer, Inc, Sensonics, Inc., TASA Group, Western Medical Assessments, and Young, Conway, Stargatt & Taylor. Dr. Doty holds stock and/or stock options in Sensonics, Inc., which sponsored research in which Dr. Doty was involved as an investigator. Dr. Tourbier has nothing to disclose. Dr. Leon-Sarmiento has nothing to disclose. Dr. Udupa has nothing to disclose. Dr. Karacali has nothing to disclose. Dr. Moonis has nothing to disclose. Dr. Beals has nothing to disclose. Dr. Fabius has nothing to disclose. Dr. Kim has nothing to disclose. Dr. Palecanda has nothing to disclose. Dr. Souza has nothing to disclose.