Anticipation of epileptic seizures from standard EEG recordings

Background New methods derived from non-linear analysis of intracranial rec ordings permit the anticipation of an epileptic seizure several minutes bef ore the seizure. Nevertheless, anticipation of seizures based on standard s calp electroencephalographical (EEG) signals has not been reported yet. The accessibility to preictal changes from standard EEGs is essential for expa nding the clinical applicability of these methods. Methods We analysed 26 scalp-EEG/video recordings, from 60 min before a sei zure, in 23 patients with temporal-lobe epilepsy. For five patients, simult aneous scalp and intracranial EEG recordings were assessed. Long-term chang es before seizure onset were identified by a measure of non-linear similari ty, which is very robust in spite of large artifacts and runs in real-time. Findings In 25 of 26 recordings, measurement of non-linear changes in EEG s ignals allowed the anticipation of a seizure several minutes before it occu rred (mean 7 min). These preictal changes in the scalp EEG correspond well with concurrent changes in depth recordings. Interpretation Scalp-EEG recordings retain sufficient dynamical information which can be used for the analysis of preictal changes leading to seizures . Seizure anticipation strategies in real-time can now be envisaged for div erse clinical applications, such as devices for patient warning, for effica cy of ictal-single photon emission computed tomography procedures, and even tual treatment interventions for preventing seizures.