The capacity of sensory hyperalgesia, hypersensitivity and hypoaesthesia to discriminate chronic whiplash associated disorders II from healthy individuals

Background: The increasing incidence of chronic whiplash associated disorders II [CWAD II ] has been attributed to poor understanding of its predominant mechanisms. Documented impairments of sensory hypersensitivity and hypoaesthesia reflect a disordered nervous system acting as triggers for symptoms. Some impairments are discriminative of CWAD II, although gender bias, non-inclusion of a widely-used sensory test [upper limb neurodynamic test (ULNT)], and conflicting findings necessitated further study. Methods: Review of the literature identified 11 sensory tests used to discriminate CWAD II from healthy individuals. The measurement properties of the tests supported preliminary reliability studies of dynamic ultrasound imaging to inform the construct validity of the ULNT, prior to its inclusion in a cross-sectional discriminative study comparing CWAD II (n=22) and healthy participants (n=36). Data analysis: Factor analysis (Eigen value _1) and logistic regression. Results: The CWAD II participants reported mild pain, disability, psychological stress, and no neuropathic pain. Three factors of hyperalgesia, hypoaesthesia and hypersensitivity were generated. Logistic regression using the factors did not discriminate between the groups (p>0.05). Conclusion: Sensory impairments exist in CWAD II, but were unable to discriminate a low severity population using 4 sensory tests. The findings support further investigation using additional tests as they emerge from the literature