Dynamic Global and Local Enhancement of Theta-Band Functional Networks as Neural Markers of Spinal Cord Stimulation Efficacy in Disorders of Consciousness.

BACKGROUND

Spinal cord stimulation (SCS) has emerged as a promising intervention for patients with disorders of consciousness (DoC). However, clinical optimization is hindered by a lack of interpretable prognostic biomarkers, and the neural mechanisms associated with recovery after SCS remain largely elusive.

METHODS

Nineteen DoC patients undergoing 70 Hz SCS were enrolled and categorized into effective (n = 9) and ineffective (n = 10) groups based on longitudinal clinical improvements. Resting-state electroencephalography (EEG) was recorded across baseline, intra-stimulation, and poststimulation phases. To investigate neural dynamics, theta-band dynamic functional connectivity (dFC) was analyzed using the weighted phase lag index (wPLI) combined with a sliding window approach. Global and local dFC metrics, alongside region-specific connectivity strengths, were quantified to characterize the global-local collaborative mechanisms induced by SCS.

RESULTS

Compared with the ineffective group, the effective group demonstrated enhanced global integration and decoupled regional segregation under SCS, evidenced by synchronized reduction in global average path length and suppression in local clustering (pTPL = 0.0090; pTLE = 0.0090; pTCC = 0.0378). Regionally, increased functional connectivity was primarily observed in the right temporal cortex (p = 0.0054), whereas decreased connectivity was identified in the left occipital region (p = 0.0218). Furthermore, dynamic EEG features were significantly correlated with 3-month CRS-R improvement scores (p < 0.05).

CONCLUSION

This dynamic global and local enhancement in the theta-band dFC serves as an interpretable neural marker for predicting SCS efficacy. These findings offer novel insights into the system-level collaborative mechanisms essential for consciousness restoration.

TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR2200061278.