Functional Connectivity Linked to Severity of Chronic Fatigue Syndrome

Brain connections
Brain connections
Decreased rs-functional connectivity across brain regions was strongly correlated with fatigue severity.

Disruptions in resting-state functional connectivity in patients with myalgicencephalomyelitis, or chronic fatigue syndrome, are significantly correlated with severity of chronic fatigue, according to findings published in Brain Connectivity.

Altered resting-state functional connectivity has been implicated in several other chronic conditions, including fibromyalgia and temporo-madibular joint disorder; however, it had not previously been explored in chronic fatigue syndrome (CFS), in which patients experience a disabling level of fatigue and cognitive abnormalities that are unresponsive to rest.

In this study, researchers from the University of Florida College of Medicine used a dual approach — data driven and model-based — to evaluate functional connectivity across brain regions in patients with CFS. Researchers enrolled 36 female participants (mean age 48.75 years), 19 with CFS and 17 healthy controls, who completed the Multidimensional Fatigue Inventory (MFI).

Using 3T MRI, the researchers investigated functional connectivity across five resting-state networks: default mode network, salience network, left and right fronto-parietal networks, and sensory-motor network. The data-driven method identified decreased intrinsic connectivity in regions within the left fronto-parietal network in patients with CFS compared to healthy controls — specifically within a region in the left superior frontal gyrus, which showed reduced coupling with the rest of the network. It also identified significantly decreased connectivity between the left anterior mid-cingulate and the sensory-motor network, and between the left posterior-cingulate cortex and the salience network. No differences in connectivity were found within the default mode network and right fronto-parietal network.

Using the Pearson’s correlation coefficient, the researchers found the strength of connectivity between brain regions to be significantly correlated with self-reported fatigue on MFI. All relationships were negative, suggesting that stronger functional connectivity between regions is associated with less severe fatigue.