Heat pain threshold and tolerance do not depend on thermode type or stimulus duration

• DOI: 10.31219/osf.io/f6ac2
• Publication Date: 2024-08-21T23:12:49Z
• Authors: Julie Parsons; Maya Joshi Delity; Jama Brookes; Titilola Akintola; Troy Dildine; Hayley Owens; Sabrina Barhoum; Julio Alejandro Y...; Lauren Yvette Atlas

Introduction: Quantitative Sensory Testing (QST) allows researchers and clinicians to evaluate variations in acute pain and thermosensation within and across individuals. With a variety of QST approaches available, it is important to evaluate whether the modality used for pain induction affects conclusions drawn from QST. We compared two types of thermodes (an Advanced Thermal Stimulator (ATS) and a Contact Heat-Evoked Potential Stimulator (CHEPS)) at two stimulus durations (8s and 3s, respectively) to assess potential differences in QST outcomes.Methods: Healthy volunteers (n = 45) underwent two adaptive staircase calibrations during the same visit, with order of thermode counterbalanced across participants. Heat was applied to 8 sites on the left volar forearm, with 24 trials per thermode.Results: There were no differences between thermodes for pain threshold, tolerance, and or correlations between temperature and pain ratings after removing outlier trials (R2, all p’s > 0.05). When outlier trials were included, we did observe a significant difference in temperature- pain correlations (p = .019), driven by higher R2 values with 8s ATS stimuli relative to 3s CHEPS stimuli. We also observed interactions with sex for both R2 measures (p’s < 0.05), such that there was no impact of thermode on temperature-pain correlations in female participants while males had lower correlations with CHEPS compared to ATS.Conclusions: These findings indicate that pain threshold and tolerance are comparable regardless of thermode size or stimulus duration, whereas the strength of the association between temperature and pain may be reduced with brief stimuli administered via CHEPS, particularly in male participants.