We carried out a Hungarian multicentre study to assess the frequency of the occurrence of warning symptoms preceding epileptic seizure. The data of 562 patients with epilepsy out of a total of 1124 were analysed on the basis of questionnaires filled in under standard conditions. About 50% of the patients experienced warning symptoms before a smaller or greater part of their seizures. Their appearance was fairly consistent and became mainly manifested in the form of headache, epigastric sensation and dysphoria. In relation to epileptological basic data, it was found that warning symptoms appeared primarily in focal epilepsies and among them they mainly preceded generalized tonic clonic and complex partial seizures. Between the warning symptom and the onset of the seizure there was usually a longer interval during which (and generally also during the warning symptom) the patient remained able to act. About 20% of the patients enrolled in the study tried to inhibit the onset or mitigate the course of the seizure and about 10% judged their spontaneous activity carried out in that direction to be successful. The frequency of the occurrence of independent prognostic symptoms not followed by a seizure was relatively low, and among epileptics with warning symptoms the incidence of seizures occurring without a preceding event was not high either. Based on our experiences, we have drawn the conclusion that, in a significant part of epileptic patients, the warning symptoms render possible the supplementation of the therapy by the development of seizure-inhibiting or seizure-avoiding behaviour or activity.

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Summary:Purpose: To assess distribution of temporal lobe spikes across different states of sleep and wakefulness in simultaneous scalp and foramen ovale (Fo) recordings.Methods: The study included 12 patients with mesial temporal lobe epilepsy (MTLE). As part of their presurgical evaluation, patients underwent long-term video-EEG monitoring with combined scalp and foramen ovale electrodes (FoEs). In addition to traditional sleep scoring, waking was subdivided into eyes-opened and eyes-closed states, and rapid-eyemovement (REM) sleep was divided into phasic and tonic states. Spike counts were carried out visually for scalp and FoEs, and spiking rates were determined for each state. A ratio between FoE and scalp spiking rates also was calculated for each state.Results: Scalp spiking showed a significant increase during NREM3,4, whereas FoE spiking increased during NREM2. The scalp/FoE ratio significantly increased during NREM3,4. A significant difference in spiking rate also was found between phasic and tonic REM states as well as between waking with eyes opened and closed in FoE recordings.Conclusions: Our data provide evidence of a discrepancy in spike distribution across different states of sleep and waking monitored by scalp and FoE recordings. We suggest that these discrepancies may reflect differences in archicortical and neocortical spike synchronization. Key Words: Mesial temporal lobe epilepsy-Sleep-Interictal spike-Foramen ovaleHippocampus.Sleep-related modulation of epileptic activity is a well-known common feature of different epilepsy syndromes. Non-rapid-eye-movement (NREM) sleep has been shown by most authors to activate interictal epileptic activity in both partial (1) and primary generalized epilepsy syndromes (2), whereas REM and waking has a contrary effect. Considerable controversy surrounds the issue of whether light NREM or deep NREM sleep exerts a stronger facilitatory effect on spiking. There is accumulating evidence that this may depend on the type of epilepsy syndrome being studied. According to recent spectral analysis results, a range of idiopathic childhood epileptic syndromes (3-8) can be characterized by increased spiking in the sigma range related to spindle synchronization present mainly during NREM2. Adult partial epilepsies, conversely, are accompanied by increased spiking related to the delta frequency range (9,10). The same tendency in spike activation was reported earlier by several visually scored studies (11-13) finding highest levels of spike activation during deep NREM stages in most temporal lobe epilepsy (TLE) patients. Nevertheless, both visually scored and spectralanalysis studies revealed small groups of patients deviating from this trend, exhibiting maximal spiking rates during light NREM, REM, or waking.A second point of controversy concerns the spiking properties of mesiotemporal structures. There are reports describing maximal spike activation mainly during deep NREM stages (11,12), whereas other authors described increased spiking mainly during light NREM stages ...

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The hypothesis that VPA decreased EEG synchronization in the delta and theta frequency bands in a use-dependent manner was supported. The findings contribute to the understanding of the action of VPA at the network level.

Generalized interictal EEG discharges are influenced by a biphasic (phase A and B) modality of arousal control during non-rapid eye movement (REM) sleep termed cyclic alternating pattern (CAP). Each phase A and the following phase B compose a CAP cycle. The percentage ratio of total CAP time to total non-REM sleep time is the CAP rate, a sleep parameter that measures the instability and fragmentation of sleep. Since CAP exerts a powerful influence on generalized interictal EEG discharges during sleep, the polysomnograms of seven epileptic patients affected by a clinically active form of primary generalized epilepsy were matched with those of seven healthy volunteers of the same age and sex to assess the influence of interictal discharges on sleep organization. No remarkable differences emerged when the traditional polysomnographic parameters were compared between the two groups. However, the epileptic patients showed significantly higher CAP rate values (52.7 vs. 34.6%; p less than 0.003), indicating a greater arousal instability in the sleep records of these subjects. Within the epileptic group, the CAP cycles that included at least one interictal paroxysm were significantly longer than those without EEG discharges (31.2 vs. 25.4 s; p less than 0.007). The selective lengthening of CAP cycles is likely due to an exaggeration of the natural activating power of phase A when coupled with EEG paroxysms and an intensification of the inhibitory properties of the following phase B. The dynamic relationships and differences between spindles in animals, k-complexes, and slow-wave bursts in humans may have a functional linkage with epileptic phenomena during sleep.