Recent research suggests that learning processes are involved in the acquisition and generalization of pain-related fear. In a voluntary movement paradigm, Geschwind and colleagues undertook a study in which movement of a joystick in one direction was followed by a pain stimulus (CS+), while movement in the opposite direction was not (CS-).1 During an acquisition phase, participants could move freely in either direction. During a transfer-of-acquisition phase, participants were provided with a signal indicating they were to move in the direction with the painful stimulus or the one without the stimulus. Finally, during the generalization phase, five additional, novel direction options were included that were similar but not identical to the initial two choices. Prior to the generalization task, participants engaged in a positive affect induction activity or a control exercise.
Participants randomized to the positive affect induction were asked to think about and write about a future in which everything goes well and they realize their dreams for 15 minutes and then visualize this scenario for 5 minutes. The control group was asked to think, write about and visualize a typical day.
In both groups, pain expectancy and fear were stronger for movements in the novel directions that were more similar to the CS+ compared to those more similar to the CS- direction. Compared to those with small or no increases in positive affect, participants with higher increases in positive affect displayed lower pain expectancy and fear of stimuli when performing movements similar to the CS- direction. Authors conclude that experimentally induced positive affect may promote safety learning by reducing pain expectancy and fear of safe movement. They suggest that positive affect may enhance safety learning through promoting generalization from known safe movements to novel yet related movements. This could boost resilience and contribute to inhibiting the transition to chronic pain. Although the authors state more research is clearly needed, they propose that patients in acute pain may benefit from interventions that increase positive affect as a strategy to limit the spread of pain-related fear. Increasing positive affect at the beginning of treatment or home exercise program may increase effectiveness by promoting safety learning.
1Geschwind N, Meulders M, Peters ML, et al. Can experimentally induced positive affect attenuate generalization of fear of movement-related pain? J of Pain. 2105;16(3):258-269.