Clinical use of Electroencephalography in the Assessment of Acute Thermal Pain: A Narrative Review Based on Articles From 2009 to 2019

Abstract

Nowadays, no practical system has successfully been able to decode and predict pain in clinical settings. The inability of some patients to verbally express their pain creates the need for a tool that could objectively assess pain in these individuals. Neuroimaging techniques combined with machine learning are seen as possible candidates for the identification of pain biomarkers. This review aimed to address the potential use of electroencephalographic features as predictors of acute experimental pain. Twenty-six studies using only thermal stimulations were identified using a PubMed and Scopus search. Combinations of the following terms were used: “EEG,” “Electroencephalography,” “Acute,” “Pain,” “Tonic,” “Noxious,” “Thermal,” “Stimulation,” “Brain,” “Activity,” “Cold,” “Subjective,” and “Perception.” Results revealed that contact-heat-evoked potentials have been widely recorded over central areas during noxious heat stimulations. Furthermore, a decrease in alpha power over central regions was revealed, as well as increased theta and gamma powers over frontal areas. Gamma and theta rhythms were associated with connectivity between sensory and affective regions involved in pain processing. A machine learning analysis revealed that the gamma band is a predominant predictor of acute thermal pain. This review also addressed the need of supplementing current spectral features with techniques that allow the investigation of network dynamics.

Accurate classification of pain experiences using wearable electroencephalography in adolescents with and without chronic musculoskeletal pain

“…Our heterogeneous sample is representative of the diverse presentations of chronic pain patients seeking clinical care and increases the generalizability of our model to various pain phenotypes. Prior literature focused predominantly on spectral EEG features, a limitation that has been noted previously ( 32 ). Our methods included spectral, entropy, functional connectivity, and graph theory feature types, many of which were previously unexplored in pediatric chronic pain participants.…”

“…Several EEG features, including spectral power derived from both fast Fourier ( 27 , 28 ) and continuous wavelet ( 29 ) transformations, functional connectivity ( 27 ), and time-frequency outcomes ( 30 , 31 ), differentiate between resting (e.g. no pain) and tonic cold pain conditions in heathy participants, with frontal theta rhythms appearing particularly sensitive to cold pain ( 32 ).…”

“…1) Most of the available studies have been conducted exclusively with adult participants. As there are distinct patterns of brain activation between adults and children in both healthy ( 32 ) and chronic pain participants ( 33 ), it is likely that these findings do not translate to adolescents. 2) Quantitative sensory testing modalities, such as the CPT, are used in chronic pain patients to differentiate between pain mechanisms, quality, and/or neurophysiological correlates, which can help guide and personalize treatment ( 34 , 35 ).…”

Electroencephalographic characteristics of children and adolescents with chronic musculoskeletal pain

“…However, the pediatric neuroimaging literature has concentrated on employing fMRI in adolescents with complex regional pain syndromes (CRPS), 24 , 41 , 66 , 71 identifying that pediatric and adult CRPS patients show different patterns of functional connectivity changes. 80 This finding supports studies identifying age-dependent developmental changes in pediatric pain processing, perception, and responses.…”

“… 2 , 7 , 17 , 30 There is substantial impetus for extending the findings of the adult chronic pain EEG literature to pediatric populations. This study used EEG to interrogate brain activity and connectivity changes, previously observed in adult studies, 66 , 74 in youth with chronic MSK pain at rest and during thermal experimental pain modalities (tonic heat and cold pressor task). We hypothesized that youth with chronic MSK pain will show developmental patterns of EEG neural activity and connectivity differences to age-matched pain-free controls at rest and an increased sensitivity to acute tonic pain experiences during thermal experimental pain modalities.…”