[Significance of complex analysis of electrical activity in temporal lobe epilepsy: foramen ovale electrodes records]

Temporal lobe epilepsy (TLE) is commonly associated with the process of synchronisation during the interictal stage, which show up as 'spikes' on neurophysiological recordings, and also with hypersynchronic activity during clinical seizures. Nevertheless, desynchronisation also seems to play an important role in the epileptogenic process, favouring the onset of seizures.

The aim of this work is to show how the latest complex network analysis techniques applied to the recordings from the foramen ovale electrodes provide valuable new information about the dynamics of mesial activity in TLE. The study also seeks to show that desynchronisation of the mesial activity plays an important role in TLE.

A cluster technique was used to analyse the recordings of six patients with TLE during the interictal stage and two seizures during the ictal period. RESULTS. Electrical activity on the ipsilateral side behaves in a less synchronic manner than that of the contralateral side. There is clearly a greater tendency in the mesial zone of the epileptic side to arrange itself in isolated groups of synchronic activity than on the contralateral side, which is organised in large groups of synchronised activity.

Analysis of the neurophysiological recordings, especially from the foramen ovale electrodes, by cluster and network analysis provides novel information that is not accessible by classical spike analysis. The greater degree of desynchronisation on the ipsilateral side would favour the appearance and origin of the seizures on that side.