The Long‐Term Prognosis of Minor Seizures in Childhood Epilepsy

Abstract

SUMMARYThe long–term clinical and electroence‐phalographic follow‐up studies were carried out for more than three to 13 years on 72 cases with minor seizures in childhood epilepsy at the Department of Pediatrics of Keio University from January 1963 to January 1973. Minor seizures were classified into typical absences, infantile spasms, Lennox syndrome, myoclonic seizures and atonic seizures. The results of each group were summarized as follows, but atonic seizures were excluded because there were too few cases of this group. Some patients with typical absences were not preceded by other epileptic seizures, while some others had generalized tonic‐clonic seizures, including febrile convulsions (mixed form by Fukuyama), prior to the onset of typical absences. Typical absences were not transformed into other epileptic seizures excluding generalized tonic‐clonic seizures at follow‐up. Twenty‐one (84%) out of 25 cases with typical absences had ceased having seizures over one year at follow‐up. Spontaneous, generalized spike and wave discharges including 3 c/s spike and wave complexes were recorded in about one half of all cases at the final interictal EEG recordings, but focal components were never seen. Mental retardation was very rare. The attacks of infantile spasms had a tendency to disappear or be converted to variously other epileptic fits, excluding typical absences, with the development of age. EEG‐findings were transformed into focal or Muse paroxysmal discharges and basic dysrhythmia from hyp‐sarhythmia after many years, but classical 3 c/s spike and wave discharges were never seen. Moderately or severely mental retardation was found in most of these patients. It was characteristic of Lennox syndrome that the improvements or successions of tonic seizures and atypical absences were repeated and diffuse slow spike and wave discharges were sustained in most of children during the periods of follow‐up. Mental retardation was found in half of all cases. Myoclonic seizures had ceased in most of children without transformations to other epileptic fits at follow‐up, but some tendency toward relative dirsculty in control of clinical seizures was noted. Two thirds of these patients were of normal intelligence, while one third had retarded intelligence at follow‐up. Based on the above–mentioned results, the literatures concerning prognosis of various types of minor seizures in childhood epilepsy were studied.