[Severity and epidemiology of myoclonic epilepsy].

The author first reviews the definition of myoclonia as an epileptic crisis differentiated from tonic crises and infantile spasms. He reviews the prevalence and incidence found in bibliographic data, under the following headings 1. Early myoclonic encephalopathy or neonatal myoclonic encephalopathy 2. Early epileptic syndrome with bursts of suppression or Otahara's syndrome. 3. West's syndrome. 4. The benign myoclonic epilepsy syndrome of children. 6. Syndrome of myoclonic epilepsy in non-progressive encephalopathy. 7. Early myoclonic epilepsy of children or Dose's syndrome. 8. Lennox-Gastaut syndrome. 9. Syndrome of epilepsy with absences in children. 10. Myoclonic absence epilepsy syndrome. 11. Landau-Kleffner syndrome and the syndrome of continuous slow spike-and-wave epilepsy during slow sleep. 12. Photosensitive epilepsy. 13. Absence epilepsy in young patients. 14. Juvenile myoclonic epilepsy. 15. Syndrome of gran mal epilepsy on waking. 16. Progressive myoclonic epilepsies. The author reviews 6,450 cases, 408 patients who had myoclonic crises, that is 6.3%. The differences seen in this total group of patients were: the myoclonic crises which presented alone, myoclonic crises accompanied by simple typical absences, those initially accompanied by generalized tonic-clonic crises and those presenting typical absences, tonic-clonic generalized crises and myoclonus simultaneously. The course of the different groups is analyzed.