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Enhanced pain and autonomic responses to ambiguous visual stimuli in chronic Complex Regional Pain Syndrome (CRPS) type I

Cohen, Helen; Hall, Jane; Harris, Nigel; McCabe, Candy; Blake, David R.; J�nig, Wilfrid

Authors

Helen Cohen

Jane Hall

Nigel Harris

Candy McCabe Candy.Mccabe@uwe.ac.uk
Professor of Clinical Research and Practice

David R. Blake

Wilfrid J�nig



Abstract

Cortical reorganisation of sensory, motor and autonomic systems can lead to dysfunctional central integrative control. This may contribute to signs and symptoms of Complex Regional Pain Syndrome (CRPS), including pain. It has been hypothesised that central neuroplastic changes may cause afferent sensory feedback conflicts and produce pain. We investigated autonomic responses produced by ambiguous visual stimuli (AVS) in CRPS, and their relationship to pain. Thirty CRPS patients with upper limb involvement and 30 age and sex matched healthy controls had sympathetic autonomic function assessed using laser Doppler flowmetry of the finger pulp at baseline and while viewing a control figure or AVS. Compared to controls, there were diminished vasoconstrictor responses and a significant difference in the ratio of response between affected and unaffected limbs (symmetry ratio) to a deep breath and viewing AVS. While viewing visual stimuli, 33.5% of patients had asymmetric vasomotor responses and all healthy controls had a homologous symmetric pattern of response. Nineteen (61%) CRPS patients had enhanced pain within seconds of viewing the AVS. All the asymmetric vasomotor responses were in this group, and were not predictable from baseline autonomic function. Ten patients had accompanying dystonic reactions in their affected limb: 50% were in the asymmetric sub-group. In conclusion, there is a group of CRPS patients that demonstrate abnormal pain networks interacting with central somatomotor and autonomic integrational pathways. © 2011 European Federation of International Association for the Study of Pain Chapters.

Journal Article Type Article
Publication Date Feb 1, 2012
Journal European Journal of Pain
Print ISSN 1090-3801
Electronic ISSN 1532-2149
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 16
Issue 2
Pages 182-195
DOI https://doi.org/10.1016/j.ejpain.2011.06.016
Keywords pain, autonomic responses, ambiguous visual stimuli, chronic, Complex Regional Pain Syndrome (CRPS)
Public URL https://uwe-repository.worktribe.com/output/950026
Publisher URL http://dx.doi.org/10.1016/j.ejpain.2011.06.016