Interoception as a neurocognitive mechanism underlying fatigue in multiple sclerosis

GONZALEZ CAMPO, CECILIA; BRUNO, DIANA; SEDEÑO, LUCAS; SINAY, VLADIMIR; SALAMONE, PAULA; GARCÍA, ADOLFO M.; PAGANI CASSARÁ, FÁTIMA; IBÁÑEZ, AGUSTÍN

Filadelfia

Congreso; 2019 Annual Meeting of the American Academy of Neurology; 2019

American Academy of Neurology

Fatigue ranks among the most common and disabling symptoms in multiple sclerosis. Although its pathophysiology is poorly understood, abundant evidence points to a key role of altered interoceptive mechanisms. However, this hypothesis has not been empirically evaluated. To bridge this gap, we integrated behavioral and neuroimaging methods to examine the relationship between interoception and fatigue in multiple sclerosis patients with and without fatigue, relative to controls. Fatigue levels in all participants were established via a validated instrument. Interoceptive accuracy was evaluated through a heartbeat detection task. Structural and functional connectivity properties of key interoceptive hubs were tested by MRI and resting-state functional MRI. Only fatigued-multiple sclerosis patients presented decreased interoceptive accuracy alongside decreased gray matter volume and increased functional connectivity in core interoceptive regions (insula and anterior cingulate cortex). Each of these alterations was directly associated with levels of fatigue. Finally, a multivariate analysis showed that a combination of the above (behavioral, structural, and functional) interoceptive indices successfully classified fatigued patients from both non-fatigued and healthy controls. Briefly, this study offers unprecedented evidence suggesting disruptions of neuronal regions and networks subserving interoception may constitute a signature of fatigue in multiple sclerosis.