THE RELATIONSHIPS BETWEEN SKIN HARDNESS, PRESSURE PERCEPTION AND 2-POINT DISCRIMINATION IN THE FINGERTIP

With the recent introduction of computer-assisted sensibility testing devices, it is possible to investigate the hypothesis that the neurolo gical mechanisms responsible for perception of pressure and two-point discrimination are influenced by skin hardness, This study examined th e relationships between the skin hardness of the human index and littl e finger pulp and the perception of pressure in 25 adults, Skin hardne ss was measured using the Derma-Durometer, Pressure perception was mea sured with the Pressure-Specified Sensory Device(R) for both static a nd moving touch stimuli and for two-point discrimination, The mean har dness of the fingertip pulp was 12.5+/-0.6 gm/mm(2). There was no stat istically significant difference in hardness between the dominant and non-dominant, right and left, index and little, or male and female fin gertips, Skin hardness was independent of age for this population, The highest correlation, which was r=0.46, was found between the cutaneou s pressure threshold for one-point static touch and skin hardness, Whi le this degree of correlation is significant at the P<0.02 level, the r(2)=21%, demonstrating that this degree of correlation leaves 79% of the variability unexplained, These results suggest a physical interact ion between mechanoreceptors and dermis that is only partially explain ed by the hardness of the skin.