Just as a ripple spreads across a pond, electroencephalography (EEG) signals in childhood absence epilepsy undergo complex changes that can be quantitatively analyzed to understand the seizure mechanisms. This study explores the temporal and spatial characteristics of EEG by combining power spectral and synchronization analysis. By comparing inter-ictal, pre-ictal, and ictal states in EEG power spectra and synchronization networks, researchers discovered that power, frequency, and spatial synchronization are enhanced during absence seizures. The initiation and propagation of these seizures involve abnormal discharge diffusion and altered synchronization networks. Additionally, the study reveals that delta rhythm is the main component during the seizures and that alpha inhibition occurs due to enhanced network connection. Understanding the temporal and spatial evolution of EEG signals not only sheds light on the transmission mechanism and clinical diagnosis of absence seizures but also has potential applications for automatic detection. Dive into the fascinating research for a deeper understanding!

ObjectiveDuring the transition from normal to seizure and then to termination, electroencephalography (EEG) signals have complex changes in time-frequency-spatial characteristics. The quantitative analysis of EEG characteristics and the exploration of their dynamic propagation in this paper would help to provide new biomarkers for distinguishing between pre-ictal and inter-ictal states and to better understand the seizure mechanisms.MethodsThirty-three children with absence epilepsy were investigated with EEG signals. Power spectral and synchronization were combined to provide the time-frequency-spatial characteristics of EEG and analyze the spatial distribution and propagation of EEG in the brain with topographic maps. To understand the mechanism of spatial-temporal evolution, we compared inter-ictal, pre-ictal, and ictal states in EEG power spectral and synchronization network and its rhythms in each frequency band.ResultsPower, frequency, and spatial synchronization are all enhanced during the absence seizures to jointly dominate the epilepsy process. We confirmed that a rapid diffusion at the onset accompanied by the frontal region predominance exists. The EEG power rapidly bursts in 2–4 Hz through the whole brain within a few seconds after the onset. This spatiotemporal evolution is associated with spatial diffusion and brain regions interaction, with a similar pattern, increasing first and then decreasing, in both the diffusion of the EEG power and the connectivity of the brain network during the childhood absence epilepsy (CAE) seizures. Compared with the inter-ictal group, we observed increases in power of delta and theta rhythms in the pre-ictal group (P < 0.05). Meanwhile, the synchronization of delta rhythm decreased while that of alpha rhythm enhanced.ConclusionThe initiation and propagation of CAE seizures are related to the abnormal discharge diffusion and the synchronization network. During the seizures, brain activity is completely changed with the main component delta rhythm. Furthermore, this article demonstrated for the first time that alpha inhibition, which is consistent with the brain’s feedback regulation mechanism, is caused by the enhancement of the network connection. Temporal and spatial evolution of EEG is of great significance for the transmission mechanism, clinical diagnosis and automatic detection of absence epilepsy seizures.

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