Discrimination between focal epilepsy and generalized epilepsy based on the spatial patterns of EEG network

Temporal lobe epilepsy (TLE), the most common form of focal epilepsy, and generalized epilepsy (GE) are two major clinical subtypes frequently encountered in clinical practice. However, due to limited understanding of their underlying pathophysiological mechanisms, distinguishing between them based solely on clinical features and conventional electroencephalographic (EEG) characteristics remains challenging. In this study, EEG was employed to investigate differences in both local and global brain activity patterns between TLE and GE across multiple frequency bands-delta, theta, alpha, beta, and gamma. Distinct rhythmic and regional patterns were identified for each subtype. Specifically, we first examined changes in local brain activity, measured as relative power spectral density. TLE was characterized by increased low-frequency (i.e., delta) neuronal synchronization, predominantly localized within the temporal and parietal lobes. In contrast, GE exhibited elevated high-frequency (i.e., beta) activity distributed across a broader range of cortical regions. With regard to global brain activity, assessed through functional connectivity, TLE showed enhanced short-range connections primarily involving the temporal lobe and adjacent areas, particularly within low-frequency bands (i.e., delta and theta). Conversely, GE demonstrated increased long-range connectivity across widespread distant brain regions, especially at higher frequency bands (i.e., alpha and beta). Based on these distinguishing features, we further conducted a classification analysis to differentiate between TLE and GE, achieving an accuracy of 82.98% when combining local and global activity measures. These findings may help elucidate the distinct pathophysiological mechanisms underlying TLE and GE, potentially offering objective biomarkers for improved diagnosis and targeted treatment strategies.