Disease duration modulates BOLD representations of alpha oscillations in drug-resistant epilepsy: A concurrent EEG...

Alpha oscillations play a fundamental role in top-down cognitive processes by regulating cortical excitability. Building on previous reports of altered alpha activity in patients with drug-resistant epilepsy (DRE), we conducted concurrent electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) studies to investigate the blood oxygen level-dependent (BOLD) correlates of alpha oscillations and assess whether these responses are modulated by disease duration.

Twenty-seven adults with focal DRE were recruited to undergo concurrent EEG and fMRI studies. Alpha oscillations were defined as the frequency range spanning from 7 Hz to the individual alpha peak frequency (IAPF) plus 2 Hz. Both relative alpha power fluctuations and epilepsy duration were included in the fMRI data analysis.

The BOLD responses associated with alpha oscillations in patients with DRE differed from those previously reported in healthy individuals. Epilepsy duration was negatively correlated with IAPF and modulated alpha-related activity in brain regions implicated in sympathetic regulation: (1) increased activation in the paracentral lobule and right anterior and posterior insular cortices, and (2) decreased activation in the bilateral angular gyri and left orbitofrontal gyrus.

These findings advance our understanding of how epilepsy interacts with the central autonomic system by revealing distinct modulation of alpha activity. Although brain imaging is critical in epilepsy assessment, MRI findings in patients with DRE are often unremarkable. This study provides an alternative approach to characterizing disease progression in DRE.