Delta/gamma band network abnormalities and enhanced phase-amplitude coupling in anti-leucine-rich glioma-inactivated 1 encephalitis.

OBJECTIVE

To characterize functional network abnormalities in patients with anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis using electroencephalogram (EEG) recordings.

METHODS

Eleven patients and eleven controls calculated relative power spectral density (PSD) and underwent functional connectivity analysis using corrected amplitude envelope correlation (AEC-c). Amplitude envelopes were extracted across five frequency bands, and network topology was analyzed by node strength. Phase-amplitude coupling (PAC) assessed cross-frequency interactions.

RESULTS

Patients showed significantly increased delta band power and decreased alpha band power (both p < 0.001). AEC-c analysis revealed reduced functional connectivity in delta (p = 0.0396) and gamma bands (p = 0.001), with delta band connectivity weakened between occipital and frontotemporal regions and gamma connectivity broadly diminished. No significant differences in node strength were observed. PAC analysis showed enhanced coupling in the frontal, parietal, temporal, and occipital regions (all p < 0.05).

CONCLUSIONS

Patients with anti-LGI1 encephalitis show increased delta and reduced alpha power, with decreased delta and gamma connectivity, while global network connectivity may remain partially stable, potentially supported by delta-gamma coupling.

SIGNIFICANCE: This study highlights altered power, network abnormalities, and enhanced coupling in anti-LGI1 encephalitis, offering new insights into its pathophysiology.