Neuropediatrics 2004; 35 - P20
DOI: 10.1055/s-2004-819395

Ictal and interictal nonlinear EEG-dynamics measured with the point prediction error (PPE) in children with temporal lobe epilepsy (TLE)

M Feucht 1, K Hoffmann 2, F Benninger 1, U Möller 2, H Witte 2
  • 1Department of Neuropsychiatry for Children and Adolescents, University Hospital, Vienna, Austria
  • 2Institute for Medical Statistics, Informatics and Documentation, FSU, Jena, Germany

Objectives: In recent years it has become evident that in the EEG recorded during, and even between seizures, typical features of nonlinear dynamics can be found which may give useful lateralizing information for the presurgical evaluation of patients with drug-resistent epilepsy.

Methods: An algorhythm was used which estimates the predictability or causality of the EEG in its time course by means of a point prediction error (PPE; based on leading Lyapunov exponent). EEGs of 25 patients were investigated (25 electrodes, 2–4 seizures per patient). Selected EEG epochs of 10min duration with interictal and ictal patterns (starting about 60min and 5min before seizure onset, respectively) were studied.

Results: In summary, each patient had an individual history of seizure onset which was characterised by an individual PPE time course at all electrodes. Patients showed repeatedly significant lower PPE values during the seizure than in the interictal epoch. Furthermore, in all epochs the spatial distribution of low PPE values was found to be congruent with the side of seizure onset (evaluated by excellent seizure outcome after epilepsy surgery).

Conclusion: The PPE seems to be a reliable estimate for lateralization of the seizure onset zone in patients with TLE.

Keywords: TLE, PPE, epilepsy surgery