title: Less efficacious conditioned pain modulation and sensory hypersensitivity in chronic whiplash-associated disorders in Singapore.
abstract: OBJECTIVE
  Cultural differences in pain perception exist. Although chronic whiplash-associated disorder (WAD) is well investigated in western countries, little is known about its presentation in Singapore. We studied the neck motion and pain sensitivity in people with chronic WAD in Singapore.
  
  
  METHODS
  Thirty chronic WAD participants (>3 mo, Neck Disability Index: 40% [SD 17%]) were age, sex, and ethnicity matched with 30 pain-free controls. All 60 participants underwent the following tests: active neck motion, pain thresholds (pressure, brachial plexus provocation test [BPPT], cold), cold pain tolerance, and conditioned pain modulation (CPM). The test stimulus of contact heat and conditioning stimulus of cold water immersion was used to assess CPM. Data were evaluated to determine differences between WAD and control groups.
  
  
  RESULTS
  Active neck motion (F1,29=80.02), pain thresholds of blunt pressure (F1,29=20.84), BPPT (F1,29=54.56), and cold (Z=-4.31) were significantly lower in participants with WAD (P<0.0001). Cold pressor pain tolerance was significantly lower in participants with WAD (Z=-2.89, P=0.02). A less efficacious CPM was also demonstrated in participants with WAD (F1,29=9.20, P=0.03). A combination of BPPT and cold hyperalgesia best predicted the WAD group (sensitivity=96.7%, specificity=96.7%).
  
  
  CONCLUSIONS
  These findings of sensory hypersensitivity and decreased neck motion in Singaporeans with chronic WAD are consistent with physical impairments reported in western populations.
authors.affiliation: †Physiotherapy Section, Department of Rehabilitation, National University Hospital, Singapore, Singapore *Division of Physiotherapy, School of Health and Rehabilitation Sciences §Centre for Clinical Excellence in Spinal Pain, Injury and Health, Division of Physiotherapy, The University of Queensland, St Lucia ‡Centre of National Research on Disability and Rehabilitation Medicine (CONROD), The University of Queensland, Herston, QLD, Australia.
authors.forename: Tze Siong
authors.initials: TS
authors.lastname: Ng
authors.forename: Ashley
authors.initials: A
authors.lastname: Pedler
authors.forename: Bill
authors.initials: B
authors.lastname: Vicenzino
authors.forename: Michele
authors.initials: M
authors.lastname: Sterling
mesh_terms: D000328:Adult; D001917:Brachial Plexus / Q000503:physiopathology; D002908:Chronic Disease / Q000453:epidemiology; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000209:etiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D009333:Neck / Q000503:physiopathology*; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology*; D010812:Physical Stimulation; D011312:Pressure; D012372:ROC Curve; D012846:Singapore / Q000453:epidemiology; D011795:Surveys and Questionnaires; D008061:Whipple Disease / Q000150:complications* / Q000453:epidemiology*