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.

Patterns of brain oscillations across different electrode montages in transcranial pulsed current stimulation

“…Knowing which network to stimulate has a marked impact on the clinical effect of tCS. For instance, in pathologies related to disruptions in the thalamo-cortical connectivity, such as schizophrenia [24] and autism [25], ear-clip tPCS could be preferred, whereas for conditions involving cortical dysfunction, specifically with reduced alpha rhythm such as neuropathic pain [6], bimastoid tPCS might be more efficient. The similarity to tACS mechanisms also widens the field of exploration between these two techniques.…”

“…tPCS delivered at an intensity of 2 mA with a randomly generated frequency ranging between 6 and 10 Hz during 20 min induces reliable electrophysiological changes in the brain [1–3]. The effects of tPCS on brain coherence and connectivity suggest that tPCS can alter cognitive functioning [4] and thus be a promising tool to treat neuropsychiatric disorders in which abnormal oscillatory patterns have been identified [5,6]. …”

Losing Ourselves: Active Inference, Depersonalization, and Meditation

“…One lens through which philosophers and cognitive scientists have been recently exploring the self is through cases where subjects report a loss, or diminishment, of their sense of self. These reports occur most prominently in the context of psychiatric disorders such as depersonalization (e.g., Colombetti and Ratcliffe, 2012 ; Seth et al, 2012 ; Miller et al, 2020 ), meditation (e.g., Britton, 2019 ; Lutz et al, 2019 ), and psychedelic drugs (e.g., Millière, 2017 ; Deane, 2020 ). The active inference framework—a popular approach to modeling action and perception that uses principles of variational Bayesian inference ( Friston et al, 2017 )—is particularly promising for understanding these phenomena.…”

“…By selfless experience, here, we mean the diminished sense of self that is reported in a wide variety of cases including depersonalization and meditative insight. Active inference and predictive processing have already been used to provide accounts of depersonalization in psychiatric contexts ( Seth et al, 2012 ; Gerrans, 2019 ), and although we find these accounts promising, we seek to build on them in important ways. In particular, we differ from existing accounts in taking affective valence and control to be central to the sense of self.…”

Does Transcranial Direct Current Stimulation Combined with Peripheral Electrical Stimulation Have an Additive Effect in the Control of Hip Joint Osteonecrosis Pain Associated with Sickle Cell Disease? A Protocol for a One-Session Double Blind, Block-Randomized Clinical Trial

“…Moreover, it appears to potentiate dysfunctional reorganization in M1 (Tsao et al, 2008 ) due to an overlap (Te et al, 2017 ), “blurring” (Tsao et al, 2011 ) and/or decreased somatotopic representation in the region (Schabrun et al, 2015 ). Chronic pain can be characterized also by abnormal EEG patterns, mainly a preponderance of slow brain rhythms such as delta (Walton et al, 2010 ), theta, and alpha (Meneses et al, 2016 ; Pinheiro et al, 2016 ). Preponderance of slow rhythms might result from significant changes in the thalamocortical loop due to sensitization of structures involved in nociceptive processing (Llinas et al, 1999 ).…”