Site-specific visual feedback reduces pain perception.
Unlike most other body parts, the back cannot be seen directly. The representation in the somatosensory and motor areas of the brain is only small compared to, for example, the hands. Disruption of body image is seen in several chronic pain states. The influence of seeing one’s back during painful stimulation on pain perception is not well known.
In this study 18 patients with chronic back pain and 18 healthy controls were tested. Painful pressure and subcutaneous electrical stimuli were applied over the trapezius muscle. Meanwhile, subjects watched an image of either their back or their hand, taken by a video camera behind them.
Subjects had to rate pain intensity and unpleasantness after each stimulation. The perceived pain intensity was lower during visual feedback of the back compared to the hand in both patients and subject. These reductions were comparable to other physical treatments, but not significant. This study compared vision of the affected body area compared to viewing the hand as a reference, instead of using a neutral object. This can be considered one of the limitations of this study.
Further research should investigate the effects of visual feedback of the site of pain in combination with other interventions such as physiotherapy or joint manipulation. > From: Diers et al., Pain 154 (2013) 890–6. All rights reserved to Elsevier B.V.
The Pubmed summary of the article can be found here.
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