Fatigue in multiple sclerosis is associated with multimodal interoceptive abnormalities.

Area of Science:

• Neuroscience
• Medical Imaging
• Clinical Psychology

Background:

• Fatigue is a prevalent and debilitating symptom in multiple sclerosis (MS).
• Previous theories suggest a link between MS fatigue and interoceptive mechanism alterations.
• Empirical validation of this hypothesis was lacking.

Purpose of the Study:

• To investigate the association between fatigue in MS patients and disruptions in the interoceptive domain.
• To identify specific behavioral, structural, and functional interoceptive changes related to MS fatigue.

Main Methods:

• Fatigue assessed using the Modified Fatigue Impact Scale.
• Interoception measured via heartbeat detection task.
• Brain structure and function evaluated using MRI and resting-state fMRI.
• Machine learning used for classification.

Main Results:

• Fatigued MS patients showed reduced interoceptive accuracy, decreased gray matter volume, and increased functional connectivity in interoceptive regions (insula, anterior cingulate cortex).
• These alterations positively correlated with fatigue severity.
• Machine learning models accurately distinguished fatigued MS patients (>90% AUC).

Conclusions:

• Neurocognitive disruptions in interoception are strongly associated with fatigue in MS.
• These findings suggest interoceptive alterations may be a signature of MS-related fatigue.
• This research provides novel insights into the pathophysiology of MS fatigue.