Comparison of The Tactile Sensitivity of Tongue and Fingertip Using a Pure-Tactile Task

The human tongue perceives various textures through the sensitivity to tactile stimuli. Previously, studies attempting to assess point-and-edge (P&E) sensitivity in both the fingers and tongue relied on stereognostic tasks, which involve a shape recognition component, and were thus inherently cognitive. Consequently, it was unclear if differences between individuals' ability on these tasks were due to differences in tactile acuity or differences in cognitive processing ability. The objective of this research was to utilize novel stimuli to assess the relative P&E sensitivity of the fingertip and tongue in a pure-tactile task, independent from a cognitive component. We hypothesized the tongue would be better than fingertip at assessing point-and-edge stimuli as previous work has found the tongue to be more sensitive to other "pure-tactile" stimuli. Thirty participants' (aged 18-30), oral and lingual sensitivity to point-and-edge stimuli was assessed using the forced-choice, up-down staircase method. Stimuli consisted of 3-D printed tiles. The height of the step was consistent across all tiles, but the angle of the step perpendicular to the tile surface varied from 45-90°. A two-tailed t-test (α=0.05) found that the JND for the tongue (12.75±1.21) was significantly smaller (p=0.0002) than the JND for the fingertip (19.81±1.75). A significant majority of subjects were more sensitive with their tongues compared to their fingertips (22/30; p=0.016). Delta JND (ΔJND) was calculated by comparing the relative differences in JNDs between individuals who were better with their tongues (n=22; 10.57±1.21) and individuals who were better with their fingers (n=8; 2.95±1.75). Individuals who were better with their tongues had significantly (p=0.000633) larger ΔJND's compared to individuals who were better with their finger.A one-year embargo was granted for this item.Academic Major: Food Science and Technolog