Assessing pain perception using the Painmatcher in patients with whiplash-associated disorders.

Abstract

OBJECTIVE: To evaluate the Painmatcher, in terms of reliability, and to explore the relationship between pain magnitude matching and pain threshold assessments in patients with whiplash-associated disorders. Also, to investigate gender differences in pain thresholds and explore the correlation between pain-related cognitions and pain threshold. DESIGN: A test-retest study. SUBJECTS: Forty-seven patients with whiplash-associated disorders. METHOD: A visual analogue scale and a Painmatcher (an instrument for comparing pain magnitude) were used to evaluate pain intensity. Pain threshold was assessed using the Painmatcher. Pain-related cognitions were assessed using the Painometer and the Tampa Scale for Kinesiophobia. RESULTS: The Painmatcher demonstrated reliable pain magnitude matching scores, but the pain threshold assessment indicated a systematic disagreement. Women exhibited significantly lower pain thresholds than men (p < 0.01). There was a weak but significant correlation between the pain intensity according to the visual analogue scale and the Painmatcher (r = 0.46) (p < 0.01). There was a significant correlation between the emotional experience of pain and pain threshold (r = -0.33) (p < 0.001), but no significant correlation between fear of movement/(re)injury and pain threshold. CONCLUSION: Measuring pain with the Painmatcher is a reliable method, but may include a possible bias in threshold assessments and seems to be associated with unpleasantness.