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Homotopic stimulation can reduce the area of allodynia in patients with neuropathic pain
Author(s) -
LoveJones Sarah J.,
Besson Marie,
Steeds Charlotte E.,
Brook Peter,
Chizh Boris A.,
Pickering Anthony E.
Publication year - 2009
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.2008.11.018
Subject(s) - allodynia , neuropathic pain , medicine , anesthesia , postherpetic neuralgia , stimulation , neuralgia , noxious stimulus , diffuse noxious inhibitory control , nociception , hyperalgesia , receptor
Allodynia is a common, troublesome feature of neuropathic pain conditions. In a previous study of postherpetic neuralgia we observed that repeated tactile stimulation appeared to reduce the size of the area of allodynia in some patients. We have undertaken a pragmatic clinical study to characterise this phenomenon in neuropathic pain patients with a range of different aetiologies. Neuropathic pain patients with a discrete area of tactile allodynia were recruited ( n =20). We assessed the sensitive area using punctate and dynamic tactile stimuli, and thermal quantitative sensory testing. On two separate testing visits, the patients had repeated (10× over 1min) noxious heat or cotton bud strokes applied to the affected site or contralaterally. Tactile stimulation of the affected area evoked pain (median 7 NRS) and a reduction (>30%) in the area of allodynia in 9/18 patients (maximum − 48±9%, after 20min), although the intensity of allodynic pain was unchanged. This effect persisted for over 1h and was present the following day in all patients tested ( n =5/5). No subjects showed an increase in area after allodynic stimulation. There was no change in heat pain threshold at a distant site following allodynic stimulation, suggesting no activation of diffuse noxious inhibitory control. Repeated thermal noxious stimulation (median NRS 7) could also elicit changes (>30%) in the area of allodynia in some patients (reductions in 7/20, increases in 3/20). Thus, we have found that a brief period of homotopic painful stimulation can reduce the area of allodynia in around half of patients with established neuropathic pains.