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Papers of the Week

Papers: 17 Aug 2019 - 23 Aug 2019

Human Studies

2020 Mar - Apr

J Pain



Usefulness of Ramp & Hold Procedures for Testing of Pain Facilitation in Human Participants: Comparisons with Temporal Summation of Second Pain.


Staud R, Godfrey MM, Mejia M, Ramanlal R, Riley JL, Robinson ME
J Pain. 2020 Mar - Apr; 21(3-4):390-398.
PMID: 31425887.


Quantitative sensory testing (QST) is used to systematically interrogate normal responding and alterations of nervous system function, including pain related central sensitization (CS). However, up to now QST of CS in human subjects has been mostly focused on temporal summation of second pain (TSSP), has been difficult to perform, and has been associated with low reliability. In contrast, slow ramp & hold (RH) procedures are simpler tests of temporal summation and easier to perform. We examined the usefulness of RH procedures as reliable generators of CS using two validated QST procedures: decay of pain aftersensations and wind-down. Twenty-seven pain-free subjects (74% female) were enrolled into the study. Trains of sensitivity adjusted TSSP or RH heat stimuli were applied to the hands of participants to achieve moderate temporal pain summation [50 NRS (0-100)]. Fifteen second aftersensations and 30s wind-down related to TSSP or RH were used for CS comparisons. Reliability of all test procedures was tested over 24 h. Use of sensitivity adjusted TSSP and RH heat stimuli resulted in average pain ratings of 48.2 and 49.6 NRS, respectively. Aftersensations or wind-down decay were not significantly different after either TSSP or RH, (all p > .05), indicating that each procedure achieved similar levels of short-term CS. Sensitivity adjusted RH stimuli were well tolerated and resulted in reliable pain increases of 50 NRS. The magnitude of short-term CS, determined by aftersensations and wind-down was similar after sensitivity-adjusted TSSP and RH stimuli (p > .05), suggesting that pain facilitation of healthy participants and likely chronic pain patients can not only be tested with TSSP but also with RH procedures. Perspective: This article examines the ability of RH procedures to generate similar central sensitivity augmentation than TSSP. The results suggest that RH is similarly well suited as TSSP to explore central pain mechanisms in healthy subjects and most likely also in chronic pain patients.