title: Patients with Rheumatoid Arthritis and Chronic Pain Display Enhanced Alpha Power Density at Rest.
abstract: Patients with chronic pain due to neuropathy or musculoskeletal injury frequently exhibit reduced alpha and increased theta power densities. However, little is known about electrical brain activity and chronic pain in patients with rheumatoid arthritis (RA). For this purpose, we evaluated power densities of spontaneous electroencephalogram (EEG) band frequencies (delta, theta, alpha, and beta) in females with persistent pain due to RA. This was a cross-sectional study of 21 participants with RA and 21 healthy controls (mean age = 47.20; SD = 10.40). EEG was recorded at rest over 5 min with participant's eyes closed. Twenty electrodes were placed over five brain regions (frontal, central, parietal, temporal, and occipital). Significant differences were observed in depression and anxiety with higher scores in RA participants than healthy controls (p = 0.002). Participants with RA exhibited increased average absolute alpha power density in all brain regions when compared to controls [F (1.39) = 6.39, p = 0.016], as well as increased average relative alpha power density [F (1.39) = 5.82, p = 0.021] in all regions, except the frontal region, controlling for depression/anxiety. Absolute theta power density also increased in the frontal, central, and parietal regions for participants with RA when compared to controls [F (1, 39) = 4.51, p = 0.040], controlling for depression/anxiety. Differences were not exhibited on beta and delta absolute and relative power densities. The diffuse increased alpha may suggest a possible neurogenic mechanism for chronic pain in individuals with RA.
authors.affiliation: Graduate Program in Medicine and Health, School of Medicine, Federal University of BahiaSalvador, Brazil; Functional Electrostimulation Laboratory, Biomorphology Department, Health Sciences Institute, Federal University of BahiaSalvador, Brazil.
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Meneses
authors.affiliation: Functional Electrostimulation Laboratory, Biomorphology Department, Health Sciences Institute, Federal University of Bahia Salvador, Brazil.
authors.forename: Fernanda C
authors.initials: FC
authors.lastname: Queirós
authors.affiliation: Department of Psychology, Research Institute of Health Sciences, University of Balearic Islands Palma de Mallorca, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Montoya
authors.affiliation: Nucleus of Innovation and Technology in Rehabilitation, Institute of Physics, Federal University of Bahia Salvador, Brazil.
authors.forename: José G V
authors.initials: JG
authors.lastname: Miranda
authors.affiliation: Graduate Program in Medicine and Health, School of Medicine, Federal University of BahiaSalvador, Brazil; Functional Electrostimulation Laboratory, Biomorphology Department, Health Sciences Institute, Federal University of BahiaSalvador, Brazil; Physiotherapy Program, Bahia School of Medicine and Public HealthSalvador, Brazil.
authors.forename: Selena M
authors.initials: SM
authors.lastname: Dubois-Mendes
authors.affiliation: Functional Electrostimulation Laboratory, Biomorphology Department, Health Sciences Institute, Federal University of BahiaSalvador, Brazil; Physiotherapy Program, Bahia School of Medicine and Public HealthSalvador, Brazil.
authors.forename: Katia N
authors.initials: KN
authors.lastname: Sá
authors.affiliation: Functional Electrostimulation Laboratory, Biomorphology Department, Health Sciences Institute, Federal University of Bahia Salvador, Brazil.
authors.forename: Cleber
authors.initials: C
authors.lastname: Luz-Santos
authors.affiliation: Graduate Program in Medicine and Health, School of Medicine, Federal University of BahiaSalvador, Brazil; Functional Electrostimulation Laboratory, Biomorphology Department, Health Sciences Institute, Federal University of BahiaSalvador, Brazil; Physiotherapy Program, Bahia School of Medicine and Public HealthSalvador, Brazil.
authors.forename: Abrahão F
authors.initials: AF
authors.lastname: Baptista
keywords: EEG; alpha rhythm; beta rhythm; chronic pain; delta rhythm; rheumatoid arthritis; theta rhythm