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Pain and other symptoms of CRPS can be increased by ambiguous visual stimuli – An exploratory study
Author(s) -
Hall Jane,
Harrison Simon,
Cohen Helen,
McCabe Candida S.,
Harris N.,
Blake David R.
Publication year - 2011
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1016/j.ejpain.2010.04.009
Subject(s) - complex regional pain syndrome , somatosensory system , sensory system , perception , multisensory integration , psychology , stimulus modality , nociception , stimulus (psychology) , medicine , physical medicine and rehabilitation , visual perception , audiology , neuroscience , physical therapy , cognitive psychology , receptor
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 two images: a bistable spatial image and a control image. For each image participants recorded the frequency of percept change in 1min 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.