» Articles » PMID: 39333624

Understanding Inter-individual Variability of Experimental Pain Habituation and Conditioned Pain Modulation in Healthy Individuals

Overview
Journal Sci Rep
Specialty Science
Date 2024 Sep 27
PMID 39333624
Authors
Affiliations
Soon will be listed here.
Abstract

Although reduced experimental pain habituation is proposed as a proxy of diminished endogenous pain modulatory capacity in chronic pain, prior studies show contradictory findings. Even across healthy participants, pain habituation varies substantially, which may relate to another measure of endogenous pain modulation, i.e., conditioned pain modulation (CPM). Hence, this study investigated the relationship between pain habituation and CPM. Pain habituation was assessed in 45 healthy participants between two blocks of 15-20 contact-heat stimuli applied to the hand. Habituation of subjective pain ratings and objective neurophysiological readouts (contact-heat evoked potential (CHEP) and palmar sympathetic skin response (SSR)) was investigated. CPM was assessed by comparing heat pain thresholds before and after hand immersion in a noxious cold (9 °C) and lukewarm water bath (32 °C, to control for repeated measures effects). Pain habituation showed a large variability, with subjective but not objective pain habituation correlating with cold-induced CPM effects (r = 0.50; p = 0.025). This correlation was not observed for 'true' CPM effects (corrected for repeated measures effects) nor for CPM effects induced by a lukewarm water bath. These findings suggest that the observed variability in subjective pain habituation may be influenced by both descending endogenous pain modulation and peripheral adaptation processes associated with repeated measures. Objective pain habituation readouts, i.e., CHEPs and SSRs, capture different, complementary aspects of endogenous pain modulation.

References
1.
Rainville P, Duncan G, Price D, Carrier B, Bushnell M . Pain affect encoded in human anterior cingulate but not somatosensory cortex. Science. 1997; 277(5328):968-71. DOI: 10.1126/science.277.5328.968. View

2.
Vogt B . Pain and emotion interactions in subregions of the cingulate gyrus. Nat Rev Neurosci. 2005; 6(7):533-44. PMC: 2659949. DOI: 10.1038/nrn1704. View

3.
Bingel U, Schoell E, Herken W, Buchel C, May A . Habituation to painful stimulation involves the antinociceptive system. Pain. 2007; 131(1-2):21-30. DOI: 10.1016/j.pain.2006.12.005. View

4.
van der Miesen M, Joosten E, Kaas A, Linden D, Peters J, Vossen C . Habituation to pain: self-report, electroencephalography, and functional magnetic resonance imaging in healthy individuals. A scoping review and future recommendations. Pain. 2023; 165(3):500-522. PMC: 10859850. DOI: 10.1097/j.pain.0000000000003052. View

5.
Kramer J, Haefeli J, Jutzeler C, Steeves J, Curt A . Improving the acquisition of nociceptive evoked potentials without causing more pain. Pain. 2012; 154(2):235-241. DOI: 10.1016/j.pain.2012.10.027. View