George A. van Aken (NIZO Food Research, Ede, The Netherlands), "Acoustic emission measurement of rubbing and tapping contacts of skin and tongue surfaces in relation to tactile perception," Food Hydrocolloids Volume 31, Issue 2, June 2013, Pages 325--331. http://dx.doi.org/10.1016/j.foodhyd.2012.11.020 Abstract: The application of acoustic emission measurement ("acoustic tribology") is explored for in vivo characterization of rubbing and tapping contacts of the biological tissues of skin and tongue. This acoustic signal originates from physical processes that are closely related to the rapid force fluctuations that are sensed by the rapidly-adapting mechanoreceptors involved in the sensation of touch. Demonstrated is the recording and analysis of sound produced by rubbing and tapping the skin against various surface textures of common materials and by rubbing the tongue against the palate or against food material in the mouth for 1 individual. The technique is shown to be sensitive to skin pre-treatment and pre-meals, and is also shown to discriminate between various surface textures and food materials in a way that relates to perception. The main advantages of the technique are its time-resolution, ease of operation and the fact that it is a direct in vivo measurement of processes that are closely related to texture perception.