In patients with drug-resistant focal epilepsy requiring surgery, hippocampal sclerosis was the most common histopathological diagnosis among adults, and focal cortical dysplasia was the most common diagnosis among children. Tumors were the second most common lesion in both groups. (Funded by the European Union and others.).

Synaptic inhibition in the brain is mainly mediated by ã_aminobutyric acid (GABA) (Biggio, 1992). The effects of GABA are modulated by a powerful uptake system (Dingledine & Korn, 1985) that limits spatial diffusion of GABA and the duration of inhibitory postsynaptic potentials (IPSPs) (Isaacson et al. 1993). If GABA uptake is blocked pharmacologically, profound changes in the shape and duration of stimulus-induced IPSPs can be observed in cortical slices of experimental animals (Dingledine & Korn, 1985;Thompson & G ahwiler, 1992). Tiagabine (TGB), a lipophilic derivative of nipecotic acid, is a novel antiepileptic drug effective in controlling partial seizures (Ben-Menachem, 1995). In in vitro experiments, TGB has been shown to inhibit the uptake of GABA from the synaptic cleft into glial cells and neurons (Suzdak & Jansen, 1995). Because so much is known concerning the mechanism of action of TGB as elucidated in experiments in animals and cortical slice preparations, it may serve as a suitable substance for enabling us to learn more about the organizational principles of cortical inhibition in humans. We used transcranial magnetic stimulation (TMS) to study non-invasively the effects of blocking GABA uptake in the human motor cortex. Although the exact neuronal mechanisms leading to inhibitory or facilitatory phenomena are not known, TMS techniques are now widely used to assess intracortical excitability in certain neurological disorders and under experimental conditions (Rothwell, 1997) including neuropharmacological manipulation (Ziemann et al. 1996b). Our

Summary:We propose an epileptic seizure classification based exclusively on ictal semiology. In this semiological seizure classification (SSC), seizures are classified as follows: The SSC identifies in detail the somatotopic distribution of the ictal semiology as well as the seizure evolution. The advantages of a pure SSC, as opposed to the current classification of the International League Against Epilepsy (ILAE), which is actually a classification of electroclinical syndromes, are discussed. Key Words: Seizure classification-Ictal semiology-Auras-Motor seizures-Paroxysmal events.The International League Against Epilepsy (ILAE) introduced a seizure classification in 1981 based on clinical semiology, interictal EEG findings, and ictal EEG patterns (1). The assumption behind such a classification, which is actually a classification of electroclinical features, is the existence of a strict one-to-one correlation between clinical-ictal semiology and interictalhctal EEG findings. Detailed analysis of clinical semiology and EEG findings shows, however, that this assumption is frequently incorrect (2), particularly for infants (3).

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