Detection of Epileptic Seizures Using Phase-Amplitude Coupling in Intracranial Electroencephalography

Seizure detection using intracranial electroencephalography (iEEG) contributes to improved treatment of patients with refractory epilepsy. For that purpose, a feature of iEEG to characterize the ictal state with high specificity and sensitivity is necessary. We evaluated the use of phase-amplitude coupling (PAC) of iEEG signals over a period of 24 h to detect the ictal and interictal states. PAC was estimated by using a synchronisation index (SI) for iEEG signals from seven patients with refractory temporal lobe epilepsy. iEEG signals of the ictal state was characterised by a strong PAC between the phase of beta and the amplitude of high gamma. Furthermore, using SI values, the ictal state was successfully detected with significantly higher accuracy than by using the amplitude of high gamma alone. In conclusion, PAC accurately distinguished the ictal state from the interictal state.