Cognition mediates the relation between structural network efficiency and gait in small vessel disease

Area of Science:

• Neurology
• Neuroimaging
• Geriatrics

Background:

• Cerebral small vessel disease (SVD) is linked to gait disturbances in the elderly.
• The precise mechanisms connecting SVD, brain networks, cognition, and gait remain unclear.
• White matter hyperintensities (WMH), microbleeds, and lacunes are common SVD markers.

Purpose of the Study:

• To investigate the relationship between structural brain network efficiency, cognitive function, and gait performance in elderly individuals with SVD.
• To explore the mediating role of cognition in the association between network efficiency and gait.
• To identify specific white matter tracts involved in gait and cognition within the SVD population.

Main Methods:

• Utilized 1.5 Tesla MRI, diffusion tensor imaging (DTI)-based tractography, and graph-theoretical analysis to assess brain network global efficiency in 272 elderly subjects with SVD.
• Assessed conventional SVD markers (WMH volume, lacunes, microbleeds), gait parameters (speed, stride length), and cognitive function via neuropsychological testing.
• Employed statistical analyses to determine associations and mediation effects, controlling for conventional SVD markers.

Main Results:

• Lower global network efficiency was significantly associated with poorer gait performance (slower speed, shorter stride length), independent of SVD markers.
• Cognitive function partially mediated the relationship between global network efficiency and gait performance.
• Identified subnetworks, particularly involving frontal tracts, associated with both gait and cognitive function in SVD.

Conclusions:

• Structural network disruption, characterized by reduced global efficiency, contributes to gait disturbances in elderly individuals with SVD.
• Cognitive dysfunction plays a significant mediating role in this network-gait relationship.
• Gait is a complex cognitive process, and understanding the role of cognition is crucial for managing gait disturbances in SVD.