Some months ago I came across a novel study by Harvie and colleagues (2015); they used virtual reality to investigate the effect of overstated or understated visual information on cervical rotation in patients with neck pain. This empirical study shows that we might need to reconsider how we interpret diagnostic provocation tests in daily care, e.g. that it is not a solid measurement for primary nociceptive information or tissue provocation.
This is, of course, not entirely new. However, what is new, is that the authors show that visual information alone is capable of changing pain thresholds during cervical rotation. Due to visual feedback which overstates the real range of motion, pain is reported sooner. Thus, participants report pain at a smaller degree of rotation of the neck. Conversely, visual feedback which understates the real range of motion has the opposite effect, it increases pain thresholds. Therefore, the pain free range of motion of the neck was enlarged. In other words, and in line with other research on visual feedback in patients with chronic pain, pain can be modulated based on visual information.
In another study Wand and colleagues (2012) hypothesized that using real time visual feedback of the lower back during movement via two mirrors might be beneficial. They show that patients report less pain during movements of their lower back and that time for back pain to ease after moving was shorter during visual feedback compared to no visual feedback. In line with these findings, the study by Diers and colleagues (2013) show a similar effect; that visual feedback – correct or incorrect - has a diminishing effect on perceived experimental pain, whereas there was no such effect present of visual feedback of the hand, a region of the body from where it is normal to obtain visual feedback.
One could argue, by simply looking at the results of these empirical studies and the small but positive effects of visual feedback as a treatment, that it would be very interesting indeed to dive deeper into the intriguing topic of using visual feedback of one’s body in patients with chronic pain.
References and further reading:
Harvie, D. S., M. Broecker, et al. (2015). "Bogus visual feedback alters onset of movement-evoked pain in people with neck pain." Psychol Sci 26(4): 385-392.
Wand, B. M., V. M. Tulloch, et al. (2012). "Seeing it helps: Movement-related back pain is reduced by visualization of the back during movement." Clin J Pain 28(7): 602-608.
Diers, M., W. Zieglgänsberger, et al. (2013). "Site-specific visual feedback reduces pain perception." Pain 154(6): 890-896.