Nonlinear EEG analysis in epilepsy: Its possible use for interictal focus localization, seizure anticipation, and prevention

Several recent studies emphasize the high value of nonlinear EEG analysisparticularly for improved characterization of epileptic brain states. In this review theauthors report their work to increase insight into the spatial and temporal dynamics ofthe epileptogenic process. Specifically, they discuss possibilities for seizure anticipation,which is one of the most challenging aspects of epileptology. Although there arenumerous studies exploring basic neuronal mechanisms that are likely to be associatedwith seizures, to date no definite information is available regarding how, when, or whya seizure occurs. Nonlinear EEG analysis now provides strong evidence that theinterictal-ictal state transition is not an abrupt phenomenon. Rather, findings indicatethat it is indeed possible to detect a preseizure phase. The unequivocal definition ofsuch a state with a sufficient length would enable investigations of basic mechanismsleading to seizure initiation in humans, and development of adequate seizure preventionstrategies. Key Words: Epilepsy--Interictal state--Preictal state--Seizure anticipation--Seizure prevention--Focus localization--Nonlinear time series analysis--EEG.