Conditioning of fear to voluntary movement paired with painful heat stimulus: Experimental verification of fear avoidance model using skin potential response

恐惧-回避模型假设对疼痛运动的恐惧制约是肌肉骨骼慢性疼痛发展的基础。我们的研究使用恐惧条件反射验证了这一点。在条件反射过程中，8名健康受试者（平均年龄27.4岁）自愿移动他们的手，并以3/5的概率接受疼痛的热刺激。为了评估疼痛的恐惧，计算皮肤电位反应（SPR）和数字评定量表（NRS）评分。在没有疼痛刺激的试验中，SPR振幅和发生率以及NRS评分在有和没有手部运动的试验之间进行了比较。有手部动作的实验组各项指标均显著高于无手部动作的实验组（振幅：6.71 ± 3.70 mV vs 3.75 ± 3.06 mV，p < 0.05;发生率：88.9 ± 16.1% vs 44.5 ± 28.5%，p < 0.01; NRS评分：4.25 ± 2.81对1.33 ± 1.09，p < 0.05）。此外，在疼痛刺激后，SPR的平均峰潜伏期在条件反射后显著降低（2.73 ± 0.36 s对1.75 ± 0.36 s，p < 0.01），表明疼痛恐惧可能与引起疼痛的自主运动有关。这一发现支持了恐惧回避模型。

he fear-avoidance model assumes that fear conditioning to movement with pain underlies development of musculoskeletal chronic pain. Our study verified this using fear conditioning. During conditioning, 8 healthy subjects (mean age, 27.4 years) voluntarily moved their hands and received painful heat stimuli with a probability of 3/5 times. To evaluate the fear of pain, skin potential response (SPR) and numerical rating scale (NRS) scores were calculated. The SPR amplitude and incidence, and NRS score in the trials devoid of the painful stimuli were compared between trials with and without hand movements. All indices in the trials with hand movements were significantly higher than those in the trials without (amplitude: 6.71 ± 3.70 mV versus 3.75 ± 3.06 mV, p < 0.05; incidence: 88.9 ± 16.1% versus 44.5 ± 28.5%, p < 0.01; NRS score: 4.25 ± 2.81 versus 1.33 ± 1.09, p < 0.05). Furthermore, the mean peak latency of SPR following the painful stimuli significantly decreased after conditioning (2.73 ± 0.36 s versus 1.75 ± 0.36 s, p < 0.01), indicating that fear of pain can be associated with voluntary movements inducing pain. This finding supports the fear-avoidance model.