Electroencephalography Signatures for Conditioned Pain Modulation and Pain Perception in Nonspecific Chronic Low Back Pain—An Exploratory Study

Abstract

Conditioned pain modulation (CPM) can discriminate between healthy and chronic pain patients. However, its relationship with neurophysiological pain mechanisms is poorly understood. Brain oscillations measured by electroencephalography (EEG) might help gain insight into this complex relationship. Objective To investigate the relationship between CPM response and self-reported pain intensity in non-specific chronic low back pain (NSCLBP) and explore respective EEG signatures associated to these mechanisms. Design Cross-sectional analysis. Participants: Thirty NSCLBP patients participated. Methods Self-reported low back pain, questionnaires, mood scales, CPM (static and dynamic quantitative sensory tests), and resting surface EEG data were collected and analyzed. Linear regression models were used for statistical analysis. Results CPM was not significantly correlated with self-reported pain intensity scores. Relative power of EEG in the beta and high beta bands as recorded from the frontal, central, and parietal cortical areas were significantly associated with CPM. EEG relative power at delta and theta bands as recorded from the central area were significantly correlated with self-reported pain intensity scores while controlling for self-reported depression. Conclusions Faster EEG frequencies recorded from pain perception areas may provide a signature of a potential cortical compensation caused by chronic pain states. Slower EEG frequencies may have a critical role in abnormal pain processing.

Temporal Summation in Fibromyalgia Patients: Comparing Phasic and Tonic Paradigms

“…It is worth mentioning that this relationship, albeit maintaining the same directionality as in the univariable analysis, only became significant after the inclusion of the other variables in the model. We speculate that one possible explanantion could be that higher pain levels in the VAS could be related to more activation of emotional affective circuits, as seen in previous studies (60)(61)(62)(63)(64). Thus, one plausible explanation for the unexpected finding of an inverse relationship between pain levels and tonic pain summation is an overactivation of emotional circuits in subjects with higher baseline VAS, leading to worse anticipation of pain and leading to higher ratings of pain at the initial of the tonic protocol that attenuates in the second and third trials.…”

Resting-state electroencephalography and magnetoencephalography as biomarkers of chronic pain: a systematic review

“…Finally, 76 studies were included. 1,5–8,10,11,15,16,18–27,30–33,35,37–49,51,56,59,60,63,66–69,74–76,79,80,82,89–91,95–98,100–105,109,110,112–115,120,122,124–126 Figure 1 depicts the PRISMA flow diagram of study selection along with reasons for study exclusion at every stage.…”

Groningen Spine Cohort

“…The majority of studies (91%, n=64) on invasive treatments (with or without conservative treatment as a control) included patients that fit their criteria for either degenerative disc disease (DDD), discogenic pain, internal disc disruption or a combination thereof. Other studies selected patients with Modic type 1 or 2 changes [48], patients with CLBP and radiating pain to the lower limb(s) [52], FBSS [55], either FBSS or mechanical LBP [86], or LBP originating from the endplate [77].…”

“…The same applies to the Impact Stratification score. Only six studies could be identified in MEDLINE that reportedly used or planned to use the minimal dataset for baseline assessment and/or the Impact Stratification as an outcome measure [73][74][75][76][77][78]. Feasibility and content validity are two important aspects that influence implementation of an outcome (set) in research and clinical practice [79].…”