Spectral Power Density analysis of the resting-state as a marker of the central effects of opioid use in fibromyalgia

Maxciel Zortea,Paul Vicuña,Iraci L S Torres,Felipe Fregni,Gerardo Beltran,Rael Lopes Alves,Wolnei Caumo

doi:10.1038/s41598-021-01982-0

Abstract

Spectral power density (SPD) indexed by electroencephalogram (EEG) recordings has recently gained attention in elucidating neural mechanisms of chronic pain syndromes and medication use. We compared SPD variations between 15 fibromyalgia (FM) women in use of opioid in the last three months (73.33% used tramadol) with 32 non-users. EEG data were obtained with Eyes Open (EO) and Eyes Closed (EC) resting state. SPD peak amplitudes between EO-EC were smaller in opioid users in central theta, central beta, and parietal beta, and at parietal delta. However, these variations were positive for opioid users. Multivariate analyses of variance (ANOVAs) revealed that EO-EC variations in parietal delta were negatively correlated with the disability due to pain, and central and parietal beta activity variations were positively correlated with worse sleep quality. These clinical variables explained from 12.5 to 17.2% of SPD variance. In addition, central beta showed 67% sensitivity / 72% specificity and parietal beta showed 73% sensitivity/62% specificity in discriminating opioid users from non-users. These findings suggest oscillations in EEG might be a sensitive surrogate marker to screen FM opioid users and a promising tool to understand the effects of opioid use and how these effects relate to functional and sleep-related symptoms.

Highlights

Spectral power density (SPD) indexed by electroencephalogram (EEG) recordings has recently gained attention in elucidating neural mechanisms of chronic pain syndromes and medication use
We tested if the variations between eyes open (EO) and eyes closed (EC) states could be a suitable marker to discriminate fibromyalgia subjects exposed and not-exposed to opioid, as well as to explore if these variations of the spectral power density (SPD) were associated with disability due to pain, sleep quality, central sensitization, and other pain-related measures in fibromyalgia patients
The analyses revealed that patients in use of opioids had a smaller Eyes Open (EO)-Eyes Closed (EC) variation for peak amplitudes in central theta, central beta and parietal beta, indicated by a mean closer to zero when compared to the non-users

Summary

Introduction

Spectral power density (SPD) indexed by electroencephalogram (EEG) recordings has recently gained attention in elucidating neural mechanisms of chronic pain syndromes and medication use. The lower alpha power band during the EEG with eyes closed compared to healthy subjects may be associated with diminished sensorimotor integration in brain p rocessing[17] They may be an indicator of a dysfunction in the cortical processing to attenuate the chronic pain s ensation[18]. To the best of our knowledge, no study was published so for aiming to address the use of opioids and eyes open vs eyes closed variations (differences), other methodologies to explore EEG spectral power density (SPD) have been implemented in opioid users. We tested if the variations between eyes open (EO) and eyes closed (EC) states could be a suitable marker to discriminate fibromyalgia subjects exposed and not-exposed to opioid, as well as to explore if these variations of the SPD were associated with disability due to pain, sleep quality, central sensitization, and other pain-related measures in fibromyalgia patients

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