Conditioned pain modulation is affected by occlusion cuff conditioning stimulus intensity, but not duration

Abstract

Background: Various conditioned pain modulation (CPM) methodologies have been used to investigate diffuse noxious inhibitory control pain mechanisms in healthy and clinical populations. Occlusion cuff parameters have been poorly studied. We aimed to investigate whether occlusion cuff intensity and/or duration influenced CPM magnitudes. We also investigated the role of physical activity levels on CPM magnitude. Methods: Two studies were performed to investigate the role of intensity and duration of occlusion cuff conditioning stimulus on test stimulus (tibialis anterior pressure pain thresholds). In Study 1, conditioning stimulus intensity of 2/10 or 5/10 (duration <20 s) was evaluated using a paired-samples t-test. In Study 2, duration of 2/10 conditioning stimulus was 3 min. One-way repeated-measures ANOVA was used to investigate the effect of time (0, 1, 2 and 3 min) on CPM magnitude. Results: In Study 1, 27 healthy volunteers (mean AE SD: 24.9 years (AE4.5); eight female) demonstrated that an occlusion cuff applied to the upper arm eliciting 5/10 local pain resulted in a significant (mean AE SD: 17% AE 46%) increase in CPM magnitude, when compared to 2/10 intensity (À3% AE 38%, p = 0.026), whereas in Study 2, 25 healthy volunteers (22.5 years (AE2.7); 13 female) demonstrated that 3 min of 2/ 10 CS intensity did not result in a significant change in CPM (p = 0.21). There was no significant relationship between physical activity levels and CPM in either study (p > 0.22). Conclusions: This study demonstrated that an occlusion cuff of 5/10 conditioning stimulus intensity, when compared to 2/10, significantly increased CPM magnitude. Maintaining 2/10 conditioning stimulus for 3 min did not increase CPM magnitude. Significance: Dysfunctional conditioned pain modulation (CPM) has been associated with poor health outcomes. Various factors can influence CPM outcomes. The role of occlusion cuff conditioning stimulus intensity and duration has not been previously investigated. Intensity (5/10), but not duration of lower intensity (2/10) conditioning stimulus, affects CPM magnitude.94 Eur J Pain 22 (2018) 94--102

Delayed effects of attention on pain sensitivity and conditioned pain modulation

“…Two recent studies have used phasic test‐stimuli (Lie et al., ; McPhee & Graven‐Nielsen, ) of which one does not find CPM effects (McPhee & Graven‐Nielsen, ) while the other study does show a CPM effect (Lie et al., ). More studies indicate that the duration of a conditioning stimulus is less important for CPM effects than the intensity of the stimulus (Graven‐Nielsen et al., ; Smith & Pedler, ), however, Lie et al. () show that phasic heat stimuli can induce a CPM effect but that it is smaller compared to a tonic test stimulus.…”

“…Two recent studies have used phasic test-stimuli (Lie et al, 2017;McPhee & Graven-Nielsen, 2018) of which one does not find CPM effects (McPhee & Graven-Nielsen, 2018) while the other study does show a CPM effect (Lie et al, 2017). More studies indicate that the duration of a conditioning stimulus is less important for CPM effects than the intensity of the stimulus Smith & Pedler, 2017), however, Lie et al (2017) show that phasic heat stimuli can induce a CPM effect but that it is smaller compared to a tonic test stimulus. It may be possible that shorter stimulation time in the phasic paradigm is an essential factor in these findings and that longer, phasic test-stimuli may be preferable to shorter phasic test-stimuli.…”

Effects of repeated conditioning pain modulation in healthy volunteers

“…Pain thresholds are the most common outcome for CPM‐effects (Nir et al., ; Razavi et al., ; Zheng et al., ; Coppieters et al., ; Flood et al., , ; Naugle et al., ; Smith and Pedler, ) and both PDT and PTT can reliably assess CPM‐effects by means of the computerized pressure cuff (Graven‐Nielsen et al., ), albeit that within‐session reliability of PDT is higher compared to PTT (Imai et al., ). In this study, the CPM‐effects of the conditioning stimulus were analysed by the PDT (for PTT effects see Appendix ) from the test‐stimuli (Graven‐Nielsen et al., ).…”

Effects of Virtual Reality versus Exercise on Pain, Functional, Somatosensory and Psychosocial Outcomes in Patients with Non-specific Chronic Neck Pain: A Randomized Clinical Trial

“…The CPM test consists of the evaluation of a painful test stimulus followed by a second evaluation at the same time as a distant, painful conditioning stimulus (parallel paradigm). The test stimulus was a pressure pain threshold (PPT) measured using a 1 cm 2 tipped-diameter algometer (Force Ten TM FDX Digital Force Gauge) applied at a rate of 40 kPa/s [36]. This scale created by Scott Huskinsson in 1976 [29] was used to measure pain intensity and its evolution.…”