Using structural and functional MRI as a neuroimaging technique to investigate chronic fatigue syndrome/myalgic encephalopathy: a systematic review

Abstract

ObjectiveThis systematic review aims to synthesise and evaluate structural MRI (sMRI) and functional MRI (fMRI) studies in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME).MethodsWe systematically searched Medline and Ovid and included articles from 1991 (date of Oxford diagnostic criteria for CFS/ME) to first April 2019. Studies were selected by predefined inclusion and exclusion criteria. Two reviewers independently reviewed the titles and abstracts to determine articles for inclusion, full text and quality assessment for risk of bias.ResultssMRI studies report differences in CFS/ME brain anatomy in grey and white matter volume, ventricular enlargement and hyperintensities. Three studies report no neuroanatomical differences between CFS/ME and healthy controls. Task-based fMRI investigated working memory, attention, reward and motivation, sensory information processing and emotional conflict. The most consistent finding was CFS/ME exhibited increased activations and recruited additional brain regions. Tasks with increasing load or complexity produced decreased activation in task-specific brain regions.ConclusionsThere were insufficient data to define a unique neural profile or biomarker of CFS/ME. This may be due to inconsistencies in finding neuroanatomical differences in CFS/ME and the variety of different tasks employed by fMRI studies. But there are also limitations with neuroimaging. All brain region specific volumetric differences in CFS/ME were derived from voxel-based statistics that are biased towards group differences that are highly localised in space. fMRI studies demonstrated both increases and decreases in activation patterns in CFS/ME, this may be related to task demand. However, fMRI signal cannot differentiate between neural excitation and inhibition or function-specific neural processing. Many studies have small sample sizes and did not control for the heterogeneity of this clinical population. We suggest that with robust study design, subgrouping and larger sample sizes, future neuroimaging studies could potentially lead to a breakthrough in our understanding of the disease.

A Cartography of Differential Gene Methylation in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Different Network Roles in the Protein-Protein Interactions Network Play Different, Biologically Relevant, Roles

“…Moreover, levels of both general and mental fatigue in ME/CFS have been inversely correlated with basal ganglia activation as assessed by fMRI, potentially secondary to dopaminergic deficits (Miller et al, 2014). Numerous other neuroimaging studies also support this notion (see (Almutairi et al, 2020;Cook et al, 2017;Gay et al, 2016;Josev et al, 2019;Manca et al, 2021;Shan et al, 2020;Shan et al, 2018;Tanaka et al, 2006;Van Der Schaaf et al, 2018, 2017Wortinger et al, 2017;Wortinger et al, 2016)). Furthermore, Carandini et al (2021) found an inverse correlation between levels of mental fatigue and DA tract abnormalities in MS. Carandini et al (2021) suggested that this is evidence of dopaminergic abnormalities underlying mental fatigue, as hypothesised by Dobryakova et al (2015).…”

Dose-Effect of Long-Snake-Like Moxibustion for Chronic Fatigue Syndrome: Study Protocol for a Randomized Controlled Trial

“…Researches on the biomarkers of CFS have revealed that the disorder in neuro-immuno-endocrinological pattern is part of the pathophysiological mechanisms [30,31], and functional (non-structural) changes in the brain are found by structural and functional MRI [17], but all of them can't fully reveal a CFS-speci c measure. The research efforts are still made to seek biomarkers or new technology to aid aetiological understanding and treatment options for CFS.…”

“…So far, CFS trials into the e cacy and safety of therapies have employed the self-reported subjective measurements as the outcome assessments for evaluating subjective physical function, anxiety, depression, and pain improvement, such as the Chalder Fatigue Scale, Short Form 36 Health Survey Questionnaire (SF-36), Anxiety and Depression Scale and visual analogue pain rating scale [15]. In addition, biological markers and imaging techniques such as MRI are also used to aid clinical diagnoses and effect assessments [16,17]. In this trial, we try to use the Thermal Texture Maps (TTM)─a thermography technique of evaluating thermal signatures of the body through holistic interpretation of infrared images to aid CFS diagnosis and moxibustion dose-effect assessment.…”

Chronic Fatigue in Cancer, Brain Connectivity and Reluctance to Engage in Physical Activity: A Mini-Review

“…Several studies using brain imaging in humans confirm that the within-network connectivity of the SN is weakened in the case of chronic fatigue syndrome/myalgic encephalomyelitis and depression ( 61 – 66 ). In addition, these disorders are associated with persistent weakened connectivity between the SN and CEN and persistent strengthened connectivity between the SN and DMN ( 66 – 68 ).…”