Centre for the Psychology of Learning and Experimental Psychopathology, KU Leuven, Leuven, Belgium; Experimental Health Psychology, Maastricht University, Maastricht, The Netherlands.
Research Centre for Mathematics, Education, Econometrics and Statistics, KU Leuven, Leuven, Belgium; Research Group Quantitative Psychology and Individual Differences, KU Leuven, Leuven, Belgium.
J Pain. 2022 Sep;23(9):1616-1628. doi: 10.1016/j.jpain.2022.04.010. Epub 2022 May 1.
Pain-related fear and -avoidance crucially contribute to pain chronification. People with chronic pain may adopt costly avoidance strategies above and beyond what is necessary, aligning with experimental findings of excessive fear generalization to safe movements in these populations. Furthermore, recent evidence suggests that, when avoidance is costly, it can dissociate from fear. Here, we investigated whether concurrently measured pain-related fear and costly avoidance generalization correspond in one task. We also explored whether healthy participants avoid excessively despite associated costs, and if avoidance would decrease as a function of dissimilarity from a pain-associated movement. In a robotic arm-reaching task, participants could avoid a low-cost, pain-associated movement trajectory (T+), by choosing a high-cost non-painful movement trajectory (T-), at opposite ends of a movement plane. Subsequently, in the absence of pain, we introduced three movement trajectories (G1-3) between T+ and T-, and one movement trajectory on the side of T- opposite to T+ (G4), linearly increasing in costs from T+ to G4. Avoidance was operationalized as maximal deviation from T+, and as trajectory choice. Fear learning was measured using self-reported pain-expectancy, pain-related fear, and startle eye-blink electromyography. Self-reports generalized, both decreasing with increasing distance from T+. In contrast, all generalization trajectories were chosen equally, suggesting that avoidance-costs and previous pain balanced each other out. No effects emerged in the electromyography. These results add to a growing body of literature showing that (pain-related) avoidance, especially when costly, can dissociate from fear, calling for a better understanding of the factors motivating, and mitigating, disabling avoidance. PERSPECTIVE: This article presents a comparison of pain-related fear- and avoidance generalization, and an exploration of excessive avoidance in healthy participants. Our findings show that pain-related avoidance can dissociate from fear, especially when avoidance is costly, calling for a better understanding of the factors motivating and mitigating disabling avoidance.
疼痛相关的恐惧和回避是导致疼痛慢性化的关键因素。慢性疼痛患者可能会采用超出必要范围的昂贵回避策略，这与这些人群中对安全运动过度恐惧泛化的实验发现一致。此外，最近的证据表明，当回避代价高昂时，它可能与恐惧分离。在这里，我们在一项任务中研究了同时测量的疼痛相关恐惧和昂贵的回避泛化是否对应。我们还探讨了健康参与者是否会尽管存在相关成本，但仍过度回避，以及回避是否会随着与疼痛相关运动的差异而减少。在机器人手臂伸展任务中，参与者可以通过选择高成本非疼痛运动轨迹 (T-) 来避免低成本疼痛相关运动轨迹 (T+)，T- 和 T+ 在运动平面的两端。随后，在没有疼痛的情况下，我们在 T+和 T-之间引入了三个运动轨迹 (G1-3)，以及 T- 相反一侧的一个运动轨迹 (G4)，从 T+到 G4 的成本线性增加。回避被定义为与 T+的最大偏差，以及轨迹选择。恐惧学习使用自我报告的疼痛预期、疼痛相关恐惧和眨眼肌电图测量。自我报告的结果具有普遍性，随着与 T+的距离增加而减少。相比之下，所有的泛化轨迹都被同等选择，这表明回避成本和以前的疼痛相互平衡。肌电图中没有出现任何影响。这些结果增加了越来越多的文献表明（疼痛相关）回避，尤其是昂贵的回避，可以与恐惧分离，这需要更好地理解促使和减轻致残性回避的因素。观点：本文比较了疼痛相关恐惧和回避的泛化，并探讨了健康参与者中过度回避的问题。我们的发现表明，疼痛相关的回避可以与恐惧分离，尤其是当回避代价高昂时，这需要更好地理解促使和减轻致残性回避的因素。
