Measures of central hyperexcitability in chronic whiplash associated disorder – A systematic review and meta-analysis

ObjectivesTo synthesise the evidence for central hyperexcitability in Chronic WAD (whiplash associated disorders) with meta-analysis, and review test protocols.MethodsChronic WAD was compared to healthy controls. Studies were eligible if they used measures of central hyperexcitability with standardised procedure. Meta-analyses (where possible) were conducted.ResultsThe search yielded 27 trials of good quality and 13 were suitable for meta-analyses. Individuals with chronic WAD showed heightened sensitivity to the following tests (p < 0.05): Pressure Pain Thresholds at Head/Neck/Upper Thoracic area (H/N/UT) (SMD (Standardised mean differences) −1.36, 95% CI (confidence intervals) −1.89 to −0.82), Upper Limb (UL) (−1.33, 95% CI −2.50 to −0.16), Lower Limb (LL) (−1.01, 95% CI −1.70 to −0.33), flexor withdrawal (−0.73, 95% CI −1.11 to −0.35), Cold Pain Threshold at H/N/UT (0.91, 95% CI 0.66–1.17) and UL (0.66, 95% CI 0.37–0.94), Heat Pain Threshold at H/N/UT (−0.58, 95% CI −0.88 to −0.28), Electrocutaneous Stimulation at H/N/UT (−1.04, 95% CI −1.63 to −0.45) and LL (−0.85, 95% CI −1.67 to −0.03), and elbow extension with the Brachial Plexus Provocation Test (SMD −0.55, 95% CI −0.76 to −0.35).DiscussionThere is compelling evidence for central hyperexcitability in chronic WAD. This should be considered in the management of chronic WAD.