Time-frequency analysis of high-frequency activity at the start of epileptic seizures

High-frequency activity in the subdural electroencephalogram (SEEGs) often appears preceding full-scale epileptic seizures. This activity may provide important information about the location of epileptic foci and the propagation of seizures within the brain. To characterize this activity we applied advanced time-frequency analysis techniques, such as the cone-kernel distribution and time-frequency signal reconstruction, to multichannel SEEG data. The data shows that the high-frequency activity has a narrow bandwidth and a highly variant dominant frequency. Our results also indicate a possible interaction between this high-frequency component and other low frequency components present at the start of epileptic seizures.