Nielsen Christopher S, Price Donald D, Vassend Olav, Stubhaug Audun, Harris Jennifer R
Department of Psychology, University of Oslo, PO Box 1094 Blindern, NO-0317 Oslo, Norway Department of Mental Health, Division of Epidemiology, Norwegian Institute of Public Health, PO Box 4404 Nydalen, NO-0403, Oslo, Norway Departments of Oral and Maxillofacial Surgery and Neuroscience, University of Florida, Health Sciences Center, PO Box 100416, Gainesville, FL 32610-0416, USA Department of Clinical Odontology, University of Oslo, PO Box 1109 Blindern, NO-0317 Oslo, Norway Department of Anesthesiology, Rikshospitalet University Hospital, NO-0027 Oslo, Norway Department of Genes and Environment, Division of Epidemiology, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, NO-0403, Oslo, Norway.
Pain. 2005 Dec 15;119(1-3):65-74. doi: 10.1016/j.pain.2005.09.018. Epub 2005 Nov 17.
Heat induced pain has been shown to follow a positively accelerating power function for groups of subjects, yet the extent to which this applies to individual subjects is unknown. Statistical methods were developed for assessing the goodness of fit and reliability of the power function for data from individual subjects with the aim of using such functions for characterizing individual differences in heat-pain sensitivity. 175 subjects rated ascending and random series of contact heat stimuli with visual analogue scales for pain intensity (VAS-I) and unpleasantness (VAS-A). Curve fitting showed excellent model fit. Substitution of model estimates in place of observed VAS scores produced minimal bias in group means, about 0.3 VAS units in the ascending series and 1.0 in the random series, on a 0-100 scale. Individual power function exponents were considerably higher for the ascending than for the random series and somewhat higher for VAS-A than for VAS-I (means: ascending VAS-I=9.04, VAS-A=9.80; random VAS-I=4.95, VAS-A=5.67). The reliability of VAS estimates was high (>==.93), and for the ascending series it remained so when extrapolating 4 degrees C beyond the empirical range. Exponent reliability was high for the ascending series (VAS-I=.92; VAS-A=.91), but considerably lower for the random series (VAS-I=.69; VAS-A=.71). Individual differences constituted 60% of the total variance in pain ratings, whereas stimulus temperature accounted for only 40%. This finding underscores the importance of taking individual differences into account when performing pain studies.
对于多组受试者，热诱导疼痛已被证明遵循正加速幂函数，但这种情况在个体受试者中的适用程度尚不清楚。开发了统计方法来评估个体受试者数据的幂函数的拟合优度和可靠性，目的是使用这些函数来表征热痛敏感性的个体差异。175名受试者使用视觉模拟量表对递增和随机系列的接触热刺激的疼痛强度（VAS-I）和不适感（VAS-A）进行评分。曲线拟合显示模型拟合良好。用模型估计值代替观察到的VAS分数，在组均值中产生的偏差最小，在0-100量表上，递增系列约为0.3个VAS单位，随机系列为1.0个VAS单位。递增系列的个体幂函数指数明显高于随机系列，VAS-A的指数略高于VAS-I（均值：递增VAS-I = 9.04，VAS-A = 9.80；随机VAS-I = 4.95，VAS-A = 5.67）。VAS估计值的可靠性很高（>==.93），对于递增系列，在超出经验范围外推4摄氏度时仍然如此。递增系列的指数可靠性很高（VAS-I =.92；VAS-A =.91），但随机系列的可靠性则低得多（VAS-I =.69；VAS-A =.71）。个体差异占疼痛评分总方差的60%，而刺激温度仅占40%。这一发现强调了在进行疼痛研究时考虑个体差异的重要性。
