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Somatosensory perception in a remote pain‐free area and function of diffuse noxious inhibitory controls (DNIC) in patients suffering from long‐term trapezius myalgia
Author(s) -
Leffler AnnSofie,
Hansson Per,
Kosek Eva
Publication year - 2002
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 - 10.1053/eujp.2001.0312
Subject(s) - diffuse noxious inhibitory control , myalgia , medicine , fibromyalgia , hypoalgesia , allodynia , quantitative sensory testing , anesthesia , nociceptor , nociception , trapezius muscle , summation , threshold of pain , noxious stimulus , physical therapy , hyperalgesia , sensory system , physical medicine and rehabilitation , stimulation , electromyography , psychology , neuroscience , receptor
In patients with localized musculoskeletal pain, spread of pain and tenderness outside the primarily painful area and sometimes even generalization of pain have been reported, the latter possibly indicating a dysfunction of endogenous pain modulatory systems. The purpose of the study was to use patients with long‐term trapezius myalgia as a model to investigate the possible influence of a localized muscle pain on somatosensory processing in a remote pain‐free area and the effect of heterotopic noxious conditioning stimulation (HNCS) on ‘diffuse noxious inhibitory controls’ (DNIC) related mechanisms. Altered somatosensory processing may indicate subclinical derangement of endogenous modulatory systems. Ten patients with long‐term (≥1 year) trapezius myalgia and 10 age‐and sex‐matched healthy controls participated. Pressure pain sensitivity, low threshold mechanoreceptive function and thermal sensitivity, including thermal pain, were assessed at the right thigh before, during and following HNCS. Pain was induced in the forearm by the tourniquet test. At rest allodynia to pressure was found at the thigh in conjunction with hypoaesthesia to cold ( p < 0.03 and p < 0.01 respectively), in patients compared with controls. During HNCS, the sensitivity to pressure pain and supra‐threshold heat pain decreased in patients and controls alike ( p < 0.02 and p < 0.04 respectively) and returned to baseline following HNCS. In conclusion, in a remote non‐painful area allodynia to pressure and hypoaesthesia to cold were found in conjunction with preserved function of DNIC‐related mechanisms. Whether altered central somatosensory processing at rest may indicate a predisposition for further spread of pain is at present unclear. © 2002 European Federation of Chapters of the International Association for the Study of Pain