Lateralization Disruption and Dynamic Balance Alterations in Alzheimer's Disease: Impacts on Hemispheric Interaction...

Area of Science:

• Neuroscience
• Cognitive Science
• Medical Imaging

Background:

• Brain lateralization, or functional specialization, is crucial for adaptive cognitive function.
• Abnormal lateralization is linked to neurological disorders, but its dynamics in Alzheimer's disease (AD) are not well understood.

Purpose of the Study:

• To investigate the dynamic changes in brain laterality in Alzheimer's disease (AD) patients compared to healthy controls (HC).
• To explore the relationship between altered brain laterality and cognitive impairment in AD.

Main Methods:

• Utilized resting-state fMRI data from 109 participants (49 AD, 60 HC).
• Calculated dynamic laterality index (DLI) using sliding window analysis to assess laterality reversal (LR) and laterality fluctuation (LF).
• Employed statistical analyses to compare groups and Spearman correlations to link laterality metrics with cognitive performance.

Main Results:

• AD patients showed reduced left and increased right lateralization, especially in somatomotor (SMN) and default mode networks (DMN).
• Decreased LR and increased LF were observed in AD, indicating disrupted intra- and inter-hemispheric communication.
• These dynamic lateralization abnormalities were associated with cognitive impairment and higher vulnerability in higher-order cognitive networks.

Conclusions:

• Alzheimer's disease is characterized by a disrupted dynamic balance of brain lateralization, particularly in higher-order cortical networks.
• Abnormalities in dynamic laterality metrics may contribute to the pathophysiology and cognitive deficits observed in AD.
• The findings highlight the importance of dynamic lateralization changes in understanding AD progression.