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

Abstract

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 2 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 Numerical Rating Scale [NRS] [0−100]). Fifteen-second aftersensations and 30-second wind-down related to TSSP or RH were used for CS comparisons. Reliability of all test procedures was tested over 24 hours. 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.

Spatial tuning in nociceptive processing is driven by attention

“…Pain intensity was rated using the Verbal Rating Scale used previously 46 which ranges from 0 (no pain at all) to 100 (worst pain imaginable). Participants were instructed that they could provide any number within the 0-100 interval.…”

Is Pain Contagious? Innocuous Stimulation Can be Transformed Into the Pain Experience by Observational Learning

“…Thus, if the results were to be generalized to other age groups, it should be done with great caution. Lastly, we did not measure the physiological correlates of sensitization, but its occurrence is unlikely given the habituation trend in the control group as well as the inter-stimulus interval, which was 10 times longer than it is in a typical procedure to evoke temporal summation 41 .…”

Temporal Summation and Aftersensations of Second Pain in Women with Myofascial Temporomandibular Disorder Differ by Presence of Temporomandibular Joint Pain

“…Third, not all trials yielded summation of pain. This is not uncommon as TS involves “complex testing procedures, which are challenging to standardize and perform”, 13 and have “often been associated with ceiling or floor effects and low response rates.” 13 This common failure to yield summation may largely reflect that QST procedures for TS may not adequately translate the wind-up process seen in animals. It is unclear whether repeated failure to summate may also be informative of differences in central processes, so we included all trials, modeled all changes in pain, and explored the more extreme ≥10-point summation dichotomy.…”

“… 10 , 12 The study of aftersensations has evolved as an extension of TS procedures where pain is examined for several minutes after stimulation ceases and interpreted as a measure of central sensitization in the post stimulation period. 13 , 14 …”

“…10,12 The study of aftersensations has evolved as an extension of TS procedures where pain is examined for several minutes after stimulation ceases and interpreted as a measure of central sensitization in the post stimulation period. 13,14 Despite increasing research on endogenous pain modulation in mTMD, consistent evidence of enhanced TS in mTMD has not emerged. [6][7][8] Evidence of enhanced TS in mTMD for mechanical pain was reported by all [15][16][17][18][19] but one 20 of six studies while results for TS of heat pain were consistently null.…”