Pain and other symptoms of CRPS can be increased by ambiguous visual stimuli – an exploratory study

Hall, J., Harrison, S., Cohen, H., McCabe, C., Harris, N. and Blake, D. R. (2010) Pain and other symptoms of CRPS can be increased by ambiguous visual stimuli – an exploratory study. European Journal of Pain, 15 (1). pp. 17-22. ISSN 1090-3801 Available from:

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Background: Visual disturbance, visuo-spatial difficulties, and exacerbations of pain associated with these, have been reported by some patients with Complex Regional Pain Syndrome (CRPS). Aims: We investigated the hypothesis that some visual stimuli (i.e. those which produce ambiguous perceptions) can induce pain and other somatic sensations in people with CRPS. Methods: Thirty patients with CRPS, 33 with rheumatology conditions and 45 healthy controls viewed 2 images: a bistable spatial image and a control image. For each image participants recorded the frequency of percept change in 1 minute and reported any changes in somatosensation. Results: 73% of patients with CRPS reported increases in pain and /or sensory disturbances including changes in perception of the affected limb, temperature and weight changes and feelings of disorientation after viewing the bistable image. Additionally, 13% of the CRPS group responded with striking worsening of their symptoms which necessitated task cessation. Subjects in the control groups did not report pain increases or somatic sensations. Conclusions: It is possible to worsen the pain suffered in CRPS, and to produce other somatic sensations, by means of a visual stimulus alone. This is a newly described finding. As a clinical and research tool, the experimental method provides a means to generate and exacerbate somaesthetic disturbances, including pain, without moving the affected limb and causing nociceptive interference. This may be particularly useful for brain imaging studies.

Item Type:Article
Uncontrolled Keywords:Complex Regional Pain Syndrome, somatosensory system, visual illusion, visual stimulus
Faculty/Department:Faculty of Health and Applied Sciences
ID Code:10849
Deposited By: Professor C. McCabe
Deposited On:09 Aug 2010 12:57
Last Modified:10 Feb 2016 17:52

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