Adaptive and Compensatory Neural Signatures in Fibromyalgia: An Analysis of Resting-State and Stimulus-Evoked EEG Oscillations

Abstract

This study aimed to investigate clinical and physiological predictors of brain oscillatory activity in patients with fibromyalgia (FM), assessing resting-state power, event-related desynchronization (ERD), and event-related synchronization (ERS) during tasks. We performed a cross-sectional analysis, including clinical and neurophysiological data from 78 subjects with FM. Multivariate regression models were built to explore predictors of electroencephalography bands. Our findings show a negative correlation between beta oscillations and pain intensity; fibromyalgia duration is positively associated with increased oscillatory power at low frequencies and in the beta band; ERS oscillations in the theta and alpha bands seem to be correlated with better symptoms of FM; fatigue has a signature in the alpha band-a positive relationship in resting-state and a negative relationship in ERS oscillations. Specific neural signatures lead to potential clusters of neural adaptation, in which beta oscillatory activity in the resting state represents a more adaptive activity when pain levels are low and stimulus-evoked oscillations at lower frequencies are likely brain compensatory mechanisms. These neurophysiological changes may help to understand the impact of long-term chronic pain in the central nervous system and the descending inhibitory system in fibromyalgia subjects.

Keywords: EEG; biomarkers; chronic pain; event-related desynchronization; fibromyalgia.

Figure 1

Topographic distribution of scalp plots in resting-state EEG. (A): delta power; (B): theta power; (C): alpha power (range: 35 to 44 dB) (10 × log10 P); (D): beta power (range: 23 to 29 dB) (10 × log10 P); (E): gamma power (range: −3 to 2.3 dB) (10 × log10 P).

Figure 2

Event-related spectral perturbation (ERSP) for fibromyalgia patients under three conditions. Axes: EEG frequency bands ranging from 1 to 50 Hz. Experimental time window from 1000 ms to 7000 ms. Colors represent absolute power (−2 to 2 dB).