A seizure warning system for long-term epilepsy monitoring

We developed a system to provide a warning early in the development of a seizure with a reasonably low false alarm rate. Such a warning will improve the close observation of seizures and interaction between observers and patients early in the seizure, even in seizures having no obvious clinical manifestation. The system relies on the availability of the EEG recording of one sample seizure, which is used as a template for subsequent detection. We evaluated the performance in 24 seizure types from scalp and intracerebral recordings. It yielded a 100% detection rate and a false alarm rate averaging one false alarm every 5 hours. The warning signal was given, on average, 9.6 seconds after EEG seizure onset. The system will be useful in improving the clinical observation of seizures and may allow ictal SPECT scans to be more widely performed.