Physical, cognitive, and psychosocial fatigue are differently related to cortical complexity of superior temporal and frontal brain regions in Crohn's disease.

Abstract

Introduction: Fatigue is common in persons with Crohn's disease, negatively impacting quality of life in both active and remitted disease state. Neural correlates of fatigue in Crohn's disease are understudied, particularly relative to the separate impacts of physical, cognitive, and psychosocial fatigue. The potential moderating role of cortical complexity on the relationship between disease activity and fatigue has yet to be examined.

Methods: Forty-nine participants with Crohn's disease and 49 healthy control participants completed the Fatigue Impact Scale (which includes physical, cognitive, and psychosocial subscales) and whole-brain T1-weighted magnetic resonance imaging. Cortical complexity analyses were performed in CAT12, including within- and between-group analyses.

Results: In the Crohn's disease group, greater fatigue across all domains was associated with lower cortical complexity in the right superior temporal gyrus. Physical and cognitive impacts of fatigue were differently related to cortical complexity in the superior frontal and supramarginal gyri. Cortical complexity in the healthy control group was exclusively, positively, related to the physical impact of fatigue. The relationship between disease activity and fatigue varied relative to cortical complexity in the right superior temporal gyrus (ΔR² = 0.062, F = 5.558, p = 0.023) and the right superior frontal gyrus (ΔR² = 0.058, F = 4.059, p = 0.050).

Discussion: The present findings expand our understanding of the complex brain-gut interactions linking disease activity and fatigue in Crohn's disease relative to underlying differences in cortical complexity.