Resting-state fMRI reveals network disintegration during delirium

Area of Science:

• Neuroscience
• Cognitive Science
• Medical Imaging

Background:

• Delirium presents with cognitive deficits linked to disrupted brain region interactions.
• EEG studies suggest altered global network topology in delirium but lack anatomical localization.
• Understanding the brain's functional connectivity is crucial for deciphering delirium.

Purpose of the Study:

• To investigate the global organization of functional connectivity in delirium.
• To identify specific anatomical alterations in brain networks during delirium.
• To explore the lasting effects of delirium on brain network structure.

Main Methods:

• Analyzed resting-state functional magnetic resonance imaging (fMRI) data from 44 subjects.
• Included 9 delirious patients, 7 post-delirium patients, and 13 controls.
• Utilized minimum spanning tree analysis to examine functional network backbones.

Main Results:

• Delirium was associated with a longer network diameter and lower leaf fraction, indicating reduced integration and efficiency.
• Delirium duration correlated with a loss of network hierarchy.
• Connectivity strength was reduced in the post-delirium group compared to controls, with specific alterations in the right posterior cingulate cortex during delirium.

Conclusions:

• Delirium is characterized by the disintegration of functional interactions between distant brain areas.
• The findings suggest that delirium has a significant impact on brain network organization.
• Altered functional connectivity patterns may persist after the resolution of delirium, indicating potential long-term neurological consequences.