Previous clinical studies have already shown a correlation between dynamic functional network properties and TLE. Wendling and others found that the interaction of local interneuron connections in TLE patients is involved in the interictal to ictal state transition [14], [35]. Ponten and co-workers analyzed the network configuration of mesial TLE patients based on the synchronization likelihood [11]. They compared network topography before, during, and after a seizure. A more randomly organized network was present in the interictal state, which moved towards a more ordered configuration during seizures. Most changes occurred in the C/C-s ratio. Schindler and colleagues found a similar result in their analysis of EEG recordings of 100 epilepsy patients [12]. Their study showed an increase of C/C-s ratio and L/L-s ratio during seizure onset, and a decrease of these parameters during seizure end. Kramer and others also found a changing clustering coefficient and small world index at seizure onset [10]. Our study suggests that a long history of seizures (which induces shifts in network topology) may be related to functional changes in interictal local clustering and small world properties.
