The effect of changes in temperature and humidity on the accuracy of von Frey hairs

A series of von Frey hairs was subjected to changes in temperature and relative humidity (RH) simulating those encountered on a neonatal intensive care unit. The effect of each environmental change on their calibrated value was monitored. It was found that changes in RH significantly affected their calibration, whereas changes in temperature had a smaller effect. The results of the study indicate that the environmental conditions in which von Frey hairs are used should be taken into account.