The sense of taste is rarely assessed quantitatively outside of a limited number of academic and industrial laboratories, despite its role in influencing nutrition, the flavor of foods and beverages, and protection against ingestion of spoiled and toxic foodstuffs. This dearth reflects, in part, practical limitations of most taste tests, most notably their reliance on liquid stimuli for stimulus presentation or rinsing. In this study, a novel portable taste test that requires neither liquid tastants nor liquid rinses is described and validated within a clinic population. This test, termed the Waterless Empirical Taste Test (WETT®), uses stimuli that are embedded in pads of monometer cellulose located on disposable plastic strips applied to the tongue's surface. The test-retest and split-half reliability coefficients of the WETT® were 0.92 and 0.88, respectively. These respective coefficients for sucrose, NaCl, citric acid, caffeine, and MSG were 0.82 and 0.80, 0.78 and 0.77, 0.56 and 0.73, and 0.84 and 0.84. The WETT® exhibited comparable, in some cases higher, sensitivity than two comparison taste tests, the Whole Mouth Taste Test and the Taste Quadrant Taste Test, to age, sex, etiology (head trauma vs. upper respiratory infections), and phenylthiocarbamide (PTC) taste ability. This study demonstrates that a taste test that does not require liquids can be as reliable and sensitive as more traditional liquid-based taste tests to clinical alterations in taste function.
Keywords: Age; Ageusia; Hypogeusia; PTC; Psychophysics; Reliability; Sex differences; Taste; Validity.