Effects of hydration on tactile sensation

Abstract

The routine tasks of washing usually necessitates the immersion of parts of the body in water, which causes hydration and changes in the mechanical properties of the superficial layer of skin. To determine how hydration affects tactile sensations, the hydration and skin-surface temperature of glabrous and hairy skin was first measured under normal conditions (air), after submersion in distilled water alone and after submersion in a surfactant-water solution. In these experiments, measurements were made of the time to achieve complete hydration and the recovery time to normal levels. The uptake of water in hairy skin was found to be considerably greater than in glabrous skin, and retention was significantly prolonged by the surfactant additive. Subsequent experiments on glabrous skin, based on the results of the preceding hydration studies, measured in-air and hydrated tactile thresholds and sensation magnitudes to vibratory stimuli and to the roughness of textured surfaces. Vibrotactile detection thresholds were not affected by skin hydration, nor were sensation magnitudes to suprathreshold vibratory stimuli. However, suprathreshold perceptions of roughness were substantially altered by hydration. It is concluded that hydration and the mechanics of the skin play a major role in the perception of spatiotemporal (i.e., textured) surfaces and, thus, must be taken into account in any physiological/psychophysical model based on using such stimuli. This may not be required for models based on predominantly temporal (i.e., vibratory) stimuli.

Diminutive Digits Discern Delicate Details: Fingertip Size and the Sex Difference in Tactile Spatial Acuity

“…A positive correlation between stratum corneum thickness and finger size could account in part for the effect of finger size on acuity. Skin temperature and hydration are also greater in male than in female fingers (Verrillo et al, 1998; see also Lévêque et al, 2000). Skin temperature might plausibly increase with finger size, as larger fingers have smaller surface-tovolume ratios, so should undergo slower heat loss.…”

Haptic perception: A tutorial

“…Amazeen and Turvey (1996) proposed that the perceived weight of an obof warmth and coolness arise from physical interactions between the skin and touched surface. Ordinarily, the temperature of the skin on the hand is within 25º-36ºC (Verrillo, Bolanowski, Checkosky, & McGlone, 1998). Ambient temperatures are generally cooler than this range, which means that objects in the environment tend to conduct heat out of the skin at contact.…”

Age-related changes in cutaneous sensation in the healthy human hand

“…In the upper limb, morphological changes and decreased numbers of both myelinated afferent fibers and cutaneous receptor end-organs are thought to explain the progressive decline in sensation (Cottrell 1940;Swensson 1939in Rexed 1944Cauna 1965;O'Sullivan and Swallow 1968). Changes in the mechanics of the skin itself, including dehydration (Verrillo et al 1998), may contribute to reduced sensation with age (Woodward 1993;Vega-Bermudez and Johnson 2004). Dehydration is clinically assessed as turgor or the ability of the skin to return after deformation (Dorrington 1981).…”