fMRI distinguishes between two classes of ME/CFS
Australian researchers have discovered that patients diagnosed using 2 different criteria, International Consensus Criteria (ICC) and the Fukuda criteria, have different brain activity. The main difference between the 2 criteria is that post-exertional malaise (PEM) is not an essential symptom for diagnosis.
They used Functional magnetic resonance imaging (fMRI) to measure brain activity during a resting state and during a task. “Different regulatory connections are consistent with the impaired cognitive performance and sleep-wake cycle of ME/CFS. Different neuropathology is involved in ICC and Fukuda classes.”
Connectivity between salience and default mode networks and subcortical nodes distinguishes between two classes of ME/CFS, by Jiasheng Su, Kiran Thapaliya, Natalie Eaton-Fitch, Sonya M Marshall-Gradisnik, Leighton R Barnden in Brain Connectivity [doi.org/10.1089/brain.2022.0049] Nov 9, 2022
Research abstract
Myalgic Encephalomyelitis or Chronic Fatigue Syndrome (ME/CFS) is a debilitating disease with unknown pathophysiology. Functional MRI (fMRI) studies in ME/CFS have reported disparate connectivities for the brain salience (SA) and default mode (DMN) networks.
In this study, we acquired resting state and task fMRI with an advanced scanner for improved subject numbers: 24 healthy controls (HC) and 42 ME/CFS patients, 18 meeting International Consensus Criteria (ICC) and 24 meeting Fukuda criteria. We evaluated mean FC between SA and DMN network hub, and subcortical regions known to be involved in ME/CFS.
We tested the hypothesis that ME/CFS connectivity differed from HC and the ICC and Fukuda classes are distinguished by different connectivities with HC for different pairs of SA, DMN or subcortical hubs.
During resting state fMRI only two connections differed from HC, both for Fukuda ME/CFS and both with an SA hub. During task fMRI 10 ME/CFS connections differed from HC, 5 for ICC and 5 for Fukuda. None were common to both classes.
Eight of the 10 different connections involved an SA hub, six of 10 were weaker in ME/CFS, 4 stronger. SA connections to the hippocampus and brainstem reticular activation system (RAS) differed from and were stronger than HC. The SA mediates the relative activity of the DMN and executive networks and imbalance will have functional consequences. The RAS and hippocampus modulate cortical activation.
Different regulatory connections are consistent with the impaired cognitive performance and sleep-wake cycle of ME/CFS. Different neuropathology is involved in ICC and Fukuda classes.
Full article behind a paywall.
