A survey of influence factors on thermal threshold measurement and its normal reference ranges in healthy undergraduates

Abstract

Objective To investigate and analyze the possible factors of thermal pain threshold measurement with modified UGO Basile Biological Apparatus in human volunteers. Methods Four hundreds and ninety-six healthy undergraduates (188 male and 308 female) were received the modified UGO Basile Biological Apparatus for heat pain testing. The baseline epicutaneous temperature (BET) was measured at the right middle finger pulp, and then started to measure the thermal pain threshold. The withdrawal latency time (WLT) and epicutaneous withdrawal temperature (EWT) were recorded. One minute later the left middle finger pulp was also measured subsequently. Factors affecting heat pain were measured and the normal reference ranges of WLT and EWT were calculated. Results The results of linear regression analysis showed that the WLT and BET were negatively correlated (left r=-0.462, P 0.05) . The normal reference values of WLT (s) and EWT (℃) (left EWT 37.0-47.2, WLT<14.2; right EWT36.4-46.6, WLT<12.7) at the right point of 496 healthy undergraduates were obtained. Conclusion The thermal pain threshold measurement might be affected by the right handedness and gender has little influence for that. The normal reference ranges of the WLT and EWT at the specific points for volunteers could be served as a reference for thermal pain measurement. Key words: Thermal pain; Pain measurement; Pain threshold; Reference ranges