Dynamic Reconfiguration of Brain Functional Networks Following Cerebellar Transcranial Direct Current Stimulation as an Add-On Treatment in Stroke.

BACKGROUND

Cerebellar transcranial direct current stimulation (tDCS) has emerged as a promising adjunct therapy for motor recovery after stroke. This study aimed to investigate whether cerebellar tDCS can modulate the topologic properties of static and dynamic functional networks in patients with ischemic stroke.

MATERIALS AND

METHODS

In this randomized controlled trial, 26 patients with stroke were allocated to receive either active or sham cerebellar tDCS alongside conventional physical therapy for three weeks. Resting-state functional magnetic resonance imaging and clinical assessments using the Fugl-Meyer Assessment (FMA) and the Barthel Index (BI) were conducted before and after the intervention. Both static and dynamic functional networks were constructed, and graph theory was used to quantify global and nodal topologic properties.

RESULTS

The active tDCS group showed significantly greater improvement in FMA and BI scores compared with the sham group. Although static functional network analysis revealed no significant changes in global or nodal metrics after the intervention, dynamic network analysis showed a significant decrease in the temporal variability of several global and nodal metrics. Notably, a significant time-by-group interaction was observed for the variability of local efficiency, which decreased significantly only in the active tDCS group. This reduction in local efficiency variability correlated with improvements in BI scores.

CONCLUSIONS

Cerebellar tDCS enhanced motor recovery and activities of daily living in patients with stroke and stabilized dynamic brain network configuration without altering static network properties. The correlation between reduced temporal variability and functional improvement suggests that stabilizing the dynamic functional configurations represents a key mechanism through which cerebellar tDCS promotes neuroplasticity and functional recovery after stroke.