title: Dysfunctional pain inhibition in patients with chronic whiplash-associated disorders: an experimental study.
abstract: Inefficient endogenous pain inhibition, in particular impaired conditioned pain modulation (CPM), may disturb central pain processing in patients with chronic whiplash-associated disorders (WAD). Previous studies revealed that abnormal central pain processing is responsible for a wide range of symptoms in patients with chronic WAD. Hence, the present study aimed at examining the functioning of descending pain inhibitory pathways, and in particular CPM, in patients with chronic WAD. Thirty-five patients with chronic WAD and 31 healthy controls were subjected to an experiment evaluating CPM. CPM was induced by an inflated occlusion cuff and evaluated by comparing temporal summation (TS) of pressure pain prior to and during cuff inflation. Temporal summation was provoked by means of 10 consecutive pressure pulses at upper and lower limb location. Pain intensity of first, fifth, and 10th pressure pulse was rated. During heterotopic noxious conditioning stimulation, TS of pressure pain was significantly depleted among healthy controls. In contrast, TS was quite similar prior to and during cuff inflation in chronic WAD, providing evidence for dysfunctional CPM in patients with chronic WAD. The present study demonstrates a lack of endogenous pain inhibitory pathways, and in particularly CPM, in patients with chronic WAD, and hence provides additional evidence for the presence of central sensitization in chronic WAD.
authors.affiliation: Department of Neurology, Faculty of Medicine, University of Antwerp (UA), Antwerp, Belgium.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Daenen
authors.forename: Jo
authors.initials: J
authors.lastname: Nijs
authors.forename: Nathalie
authors.initials: N
authors.lastname: Roussel
authors.forename: Kristien
authors.initials: K
authors.lastname: Wouters
authors.forename: Michel
authors.initials: M
authors.lastname: Van Loo
authors.forename: Patrick
authors.initials: P
authors.lastname: Cras
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D002490:Central Nervous System / Q000503:physiopathology; D059350:Chronic Pain / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy; D003213:Conditioning, Psychological / Q000502:physiology; D059328:Diffuse Noxious Inhibitory Control / Q000502:physiology*; D056228:Feedback, Sensory; D005260:Female; D006801:Humans; D008297:Male; D009433:Neural Inhibition / Q000502:physiology*; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology; D017288:Pain Threshold / Q000502:physiology; D011312:Pressure; D011788:Quality of Life; D014911:Whiplash Injuries / Q000150:complications / Q000503:physiopathology* / Q000628:therapy