195: Comparative Analysis of Functional Connectivity between Fibromyalgia and Long COVID Patients

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Chronic pain related to Long COVID, Pain in Special Populations , Imaging (e.g. fMRI, PET, MRS)

Background and Aims: Fibromyalgia, characterized by generalized pain, and chronic fatigue syndrome, characterized by fatigue, are both diagnosed based on the patient's subjective complaints. Their pathogenesis remains unclear. A link between these conditions and viral infections has been suggested. Recently, many patients have complained of fatigue and generalized pain as aftereffects of COVID-19, and long COVID can be considered a pathological model for fibromyalgia and chronic fatigue syndrome after viral infection. Therefore, we conducted a comparative study of functional changes in the central nervous system between patients with long COVID and those with fibromyalgia and chronic fatigue syndrome using resting-state functional MRI analysis.

Methods: Eight patients met both the American College of Rheumatology's 2016 diagnostic criteria for fibromyalgia and the diagnostic criteria of Institute of Medicine, USA for chronic fatigue syndrome (FC group), and other eight patients reported similar symptoms as COVID-19 sequelae (COVID group). Resting-state functional MRI analysis was performed using spm12 and CONN to determine functional connectivity between brain ROIs. Connections where the difference between the two groups satisfied a False Discovery Rate adjusted p (p-FDR) < 0.05 were extracted. For other measurements, Student's t test was performed between two groups, with p < 0.05 considered significant.

Results: No significant difference in pain complaints (NRS) was observed between the FC group (7.5) and the COVID group (6.6) (p=0.45). Of 13,366 connections between 164 ROIs, 31 had a p-FDR <0.05. Among these, strong functional connectivity of 0.5 or greater was observed between the intraparietal sulcus (IPS) and the frontal eye field (FEF) in the left dorsal attention network (FC group 0.08, COVID group 0.62), and between the intraparietal sulcus (IPS) and the left superior parietal lobule in the left dorsal attention network (FC group 0.11, COVID group 0.68).

Conclusions: While some Long COVID patients complain of fatigue and dizziness without pain, this study focused on patients with similar pain complaints. The areas where significant differences were observed between the two groups are areas that affect spatial cognition, which may be related to the dizziness symptoms of Long COVID patients. As the number of cases in this study is still small, we plan to collect more cases and verify the relationship between functional connectivity and clinical symptoms.

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Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome; Board on the Health of Select Populations; Institute of Medicine Washington (DC): National Academies Press (US); 2015 Feb 10. DOI: 10.17226/19012 The National Academies Collection: Reports funded by National Institutes of Health.
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5 Aoe, T., Kawanaka, R., Ohsone, F., Hara, A. & Yokokawa, T. Functional connectivity associated with attention networks differs among subgroups of fibromyalgia patients: an observational case-control study. Sci Rep 14, 10197 (2024). https://doi.org/10.1038/s41598-024-60993-9

Presenting Author: Tomohiko Aoe
Submitting Author: Tomohiko Aoe

Senior Author: Tomohiko Aoe

IASP 2026 Global Year theme of Neuropathic Pain: No

• Ryoko Kawanaka: MD - Department of Anesthesiology, Chiba Medical Center, Teikyo University, Ichihara City, Japan.
• Yugo Tagaido: MD - Department of Anesthesiology, Chiba Medical Center, Teikyo University, Ichihara City, Japan
• Akira Hara: B.S. - Department of Radiology, Chiba Medical Center, Teikyo University, Ichihara City, Japan
• Fumio Ohsone: B.S. - Department of Radiology, Chiba Medical Center, Teikyo University, Ichihara City, Japan.