Influence of waking and sleep stages on the inter-ictal paroxysmal activity in partial epilepsy with complex seizures

Twenty-six patients suffering from partial epilepsy with complex seizures underwent polysomnographic recording. Paroxysmal activity (PA) densities in waking and sleep stages were assessed. Total PA densities of one night were found to be an increasing function of the seizure frequency in the previous period. Nineteen patients had more PA during sleep, 5 others in the waking state and the two remaining patients exhibited no differences in PA densities between sleep and waking. Nocturnal seizures were reported by patients showing the sleep PA increase pattern; they also used more anti-convulsants than patients showing the waking PA increase pattern. Differences in PA densities between these two groups were more pronounced in the more desynchronized (waking) and the more synchronized (stages 3 + 4) cortical states. The modulation by slow wave sleep stages was independent of, and superimposed on, the sleep/waking one.