Disrupted brain network topology and structural-functional decoupling in chronic post-stroke aphasia

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Language impairments in post-stroke aphasia (PSA) are linked to brain network reorganization.
• Previous research focused on single network parameters, neglecting structural-functional (S-F) coupling in PSA.

Purpose of the Study:

• To investigate S-F coupling in patients with PSA.
• To explore the relationship between network properties, S-F coupling, and language function.

Main Methods:

• Recruited 52 PSA patients and 55 normal controls (NCs).
• Constructed structural connectivity (SC) and functional connectivity (FC) networks using diffusion kurtosis imaging (DKI) and rs-fMRI.
• Applied graph theory analysis and multiscale S-F coupling calculations, followed by correlation analysis with the Western Aphasia Battery (WAB).

Main Results:

• PSA patients exhibited disrupted SC global topology (reduced efficiency, increased path length) but no significant global FC differences.
• Nodal SC properties were decreased, while FC showed hemispheric asymmetry.
• Reduced whole-brain S-F coupling and decoupling were observed in several networks, with FPN S-F coupling positively correlating with the aphasia quotient (AQ).

Conclusions:

• PSA is characterized by asymmetric disruption of network topology and multiscale S-F decoupling.
• S-F coupling in the frontoparietal network (FPN) shows potential as a neuroimaging marker for predicting language recovery in PSA.