Electroencephalographic Patterns in Chronic Pain: A Systematic Review of the Literature

Abstract

The main objective of this study is to review and summarize recent findings on electroencephalographic patterns in individuals with chronic pain. We also discuss recent advances in the use of quantitative Electroencephalography (qEEG) for the assessment of pathophysiology and biopsychosocial factors involved in its maintenance over time. Data collection took place from February 2014 to July 2015 in PubMed, SciELO and PEDro databases. Data from cross-sectional studies and longitudinal studies, as well as clinical trials involving chronic pain participants were incorporated into the final analysis. Our primary findings related to chronic pain were an increase of theta and alpha EEG power at rest, and a decrease in the amplitude of evoked potentials after sensory stimulation and cognitive tasks. This review suggests that qEEG could be considered as a simple and objective tool for the study of brain mechanisms involved in chronic pain, as well as for identifying the specific characteristics of chronic pain condition. In addition, results show that qEEG probably is a relevant outcome measure for assessing changes in therapeutic studies.

Altered theta oscillations in resting EEG of fibromyalgia syndrome patients

“…Low‐frequency spectral power increases in resting brain EEG were also reported in migraine and complex regional pain syndrome patients (Bjork et al., ; Walton et al., ), paraplegic neuropathic pain patients during imaginary movement (Vuckovic et al., ) and spinal cord injury patients with chronic pain (Jensen et al., ). This accumulation of findings was previously utilized to tentatively point towards the relevance of increased resting theta activity for broader aspects of chronic pain (Pinheiro et al., ).…”

Thalamic Bursts and the Epic Pain Model

“…Moreover, the pain-induced increase in cortical theta power is reversed upon treatment with analgesics including pregabalin and mexiletine (Leblanc et al, 2016a). Hence, our team and others have speculated that somatosensory cortical theta is a neural signature of pain in rodents (Leblanc et al, 2016a) and humans (Stern et al, 2006; Pinheiro et al, 2016). The origin of theta oscillations, however, remains elusive.…”

Thalamic Bursts Down-regulate Cortical Theta and Nociceptive Behavior

“…Overall, it has been postulated that high EEG power in the low-frequency range represents a neural correlate for pain 32 , and that thalamus plays a key role in the ‘thalamocortical dysrhythmia’ attributed to pain and other cognitive disorders 6, 33 .…”