Sleep and prolonged epileptic activity (status epilepticus).

The correlations between sleep and prolonged epileptic activity are discussed on the basis of the status classification of Gastaut (1983). Little information is available on the interrelation of sleep and the status of tonic-clonic seizures (grand mal status). Most important is the therapeutical management of these cases. Tonic seizures have been reported to occur in large numbers during NREM sleep in patients with Lennox-Gastaut syndrome. A status-like increase is possible. Tonic seizures occur almost exclusively during sleep. Myoclonic status epilepticus arising (a) in the course of primary generalized epilepsy and (b) in the course of encephalopathies, are usually markedly attenuated during sleep. In absence status (petit mal status) synchronized sleep generally fragments the continuous discharge which is replaced by isolated bursts of polyspikes, or polyspike and wave complexes. The absence status can recur upon awaking during the night or in the morning. The abnormal EEG activity of a petit mal status can, however, occasionally persist during the whole night. Improvement as well as activation during sleep have been observed in elementary (= simple) partial status epilepticus; improvement seems to be more frequent. Epilepsia partialis continua may persist or decrease during sleep. An increase as well as decrease of motor phenomena has been observed during the REM stages. 'Epileptic aphasia' of childhood is associated with subclinical bioelectric status epilepticus during sleep. The electrical status epilepticus must be delineated as a separate group. The term encephalopathy related to electrical status epilepticus during slow sleep (ESES) has been proposed on the basis of associated psychic syndromes. This form of status epilepticus disappears during the waking state and during REM sleep. Cases with hypsarrhythmia without clinical signs may also be classified under the group of electrical or bioelectrical status. In some cases, a continuous hypsarrhythmia is observed only during sleep. In this context, one must also mention those patients who demonstrate continuous activation of spikes, or spike and wave potentials (without clinical seizures) during eye closure.