The Neurophysiology and Assessment of Human Skin Wetness Perception

The ability to perceive skin wetness represents one of the numerous somatosensory features of the skin. Although the ability to sense skin wetness and humidity is critical for behavioral and autonomic adaptations, humans are not provided with specific skin receptors for sensing wetness. Hence, the ability to sense skin wetness has been suggested to rely on a complex multisensory integration of thermal (i.e., heat transfer) and tactile (i.e., mechanical pressure and skin friction) inputs generated by the interaction between skin, moisture, and (if donned) clothing. Recent evidence has confirmed this hypothesis, and the first neurophysiological model of human skin wetness perception, which helps explain how humans sense cold, neutral, and warm wetness on their skin, has been recently developed. This chapter presents the state of the current knowledge about the neurophysiological and psychophysical bases of humans’ ability to perceive skin wetness, along with an overview of the most recent methods used to assess this sensory feature of the human skin. Also, a practical outline of a typical experimental protocol, as used in the assessment of skin wetness perception, is presented.