Changes in hypsarrhythmia in West syndrome following combined high-dose prednisolone and vigabatrin therapy: A standardized, low-resolution, brain electromagnetic tomography study.

This study aimed to quantitatively assess electrophysiological changes in patients with West syndrome (WS) treated with high-dose prednisolone and vigabatrin, using standardized low-resolution brain electromagnetic tomography (sLORETA). The study included 17 infants newly diagnosed with WS. Electroencephalography (EEG) recordings were obtained before treatment and again at 4 weeks after initiating combination therapy with oral prednisolone (8 mg/kg/day) and vigabatrin (100 mg/kg/day, increased to 150 mg/kg/day if needed). Artifact-free sleep EEG epochs were analyzed using sLORETA to estimate cortical current density across delta, theta, alpha, and beta frequency bands, with statistical comparisons performed using nonparametric voxel-wise permutation testing. At 4 weeks, 11 patients (64.7%) achieved complete cessation of spasms, and hypsarrhythmia resolved in 12 patients (70.6%). sLORETA analysis revealed significant reductions in cortical current density across all frequency bands, most prominently in the delta range. These reductions were most notable in the frontal cortex, particularly in the inferior and middle frontal gyri, with additional involvement of temporal and deep cortical regions, indicating an anterior-dominant, frequency-dependent treatment effect. The suppression of low-frequency activity aligns with attenuation of the pathological slow-wave components characteristic of hypsarrhythmia, indicating that combined high-dose prednisolone and vigabatrin therapy leads to a substantial reduction in cortical hyperexcitability. These findings provide quantitative neurophysiological evidence that treatment modulates dysfunctional cortical networks in WS. Furthermore, sLORETA can be a promising method for objectively monitoring treatment response and increasing the understanding of neurophysiological mechanisms underlying developmental and epileptic encephalopathies.