Pressure pain thresholds in chronic whiplash associated disorder: Further evidence of altered central pain processing

Objective: To investigate pressure pain thresholds [PPTs] at sites both within and remote to the region involved with whiplash trauma. Methods: One hundred and fifteen subjects With chronic whiplash associated disorder [WAD] and 95 healthy asymptomatic subjects were included in the study. Pressure pain thresholds were measured at eight sites bilaterally within the cervical spine and upper limbs and a remote site in the lower limb. Results: Subjects with chronic WAD had significantly lower PPTs than the asymptomatic subjects in both local and remote sites [all P < 0.001]. There was a greater decrease of PPTs over cervical spine sites than either the upper or lower limb sites. Conclusion: The generalized decrease in PPTs in sites both local and remote to the site of injury suggests a sensitized central nervous system contributes to persistent pain experienced by WAD patients. The greater decrease in PPTs over cervical spine sites may reflect the continuing role of sensitized nociceptors within the cervical spine in the pain syndrome.