Heat pain detection threshold is associated with the area of secondary hyperalgesia following brief thermal sensitization: a study of healthy male volunteers

Abstract

Introduction

The area of secondary hyperalgesia following brief thermal sensitization (BTS) of the skin and heat pain detection thresholds (HPDT) may both have predictive abilities in regards to pain sensitivity and clinical pain states. The association between HPDT and secondary hyperalgesia, however, remains unsettled, and the dissimilarities in physiologic properties suggest that they may represent 2 distinctively different pain entities. The aim of this study was to investigate the association between HPDT and BTS-induced secondary hyperalgesia.

Methods

A sample of 121 healthy male participants was included and tested on 2 separate study days with BTS (45°C, 3 minutes), HPDT, and pain during thermal stimulation (45°C, 1 minute). Areas of secondary hyperalgesia were quantified after monofilament pinprick stimulation. The pain catastrophizing scale (PCS) and hospital anxiety and depression scale (HADS) were also applied.

Results

A significant association between HPDT and the size of the area of secondary hyperalgesia (p<0.0001) was found. The expected change in area of secondary hyperalgesia due to a 1-degree increase in HPDT was estimated to be −27.38 cm², 95% confidence interval (CI) of −37.77 to −16.98 cm², with an R² of 0.19. Likewise, a significant association between HADS-depression subscore and area of secondary hyperalgesia (p=0.046) was found, with an estimated expected change in secondary hyperalgesia to a 1-point increase in HADS-depression subscore of 11 cm², 95% CI (0.19–21.82), and with R² of 0.03. We found no significant associations between secondary hyperalgesia area and PCS score or pain during thermal stimulation.

Conclusion

HPDT and the area of secondary hyperalgesia after BTS are significantly associated; however, with an R² of only 19%, HPDT only offers a modest explanation of the inter-participant variation in the size of the secondary hyperalgesia area elicited by BTS.

Keywords:

• pain
• central nervous system sensitization
• hyperalgesia
• pain threshold
• healthy volunteers
• catastrophization
• secondary hyperalgesia
• central sensitization

View correction statement:

Heat pain detection threshold is associated with the area of secondary hyperalgesia following brief thermal sensitization: a study of healthy male volunteers [Corrigendum]

Acknowledgments

This work was supported by grants from the Augustinus foundation (grant number: 14-3907), Toyota Fonden – Denmark (grant number: OH/BG-8610), and the Aase and Ejnar Danielsen’s foundation (grant number: 10-001341). The funders had no role in the conception or design of the study, the collection, analysis or interpretation of data, the writing of the report, or on the decision to publish the results.

The authors would like to thank illustrator Sarah Egbert Eiersholt for her valuable contribution to the artwork in Figure 1.

Disclosure

The authors report no conflicts of interest in this work.