Abstract
This repot is based on 30 cases with typical absence, which were followed for more than three to fifteen years at the Department of Pediatrics of Keio University from January 1963 to December 1975.
Typiaci absence was defined as follows: The attacks were characterized by a sudden and brief disturbance of consciousness lasting 5-20 seconds without aura and postparoxysmal symptoms, either with or without minor motor, automatic and automic components, accompanied by diffuse rhythmic 3 c/sec spike-wave discharges in EEG during the attacks. The termination of the attacks was abrupt and the attacks occurred frequently.
The cases with typical absence during the period of observation totalled forty-five, but there were 33%(15 cases) of drop-outs.
Of the 30 cases, 12 (40%) were male and 18 (60%) were female. The onset of the illness occurred mostly between the fourth and ninth years of life. Their ages at the time of this report varied from seven to 26 years.
Twenty-one (70%) were not preceded by other epileptic seizures, while 9 cases (30%) suffered grand mal of febrile convulsions prior to the onset to typical absence. Transformation of clinical seizures, mental outcome and electroencephalographic findings during the follow-up were studied.
The results were summarized as follows:
1) Of all 30 patients who had ceased to have attacks of typical absence at the follow-up study, 27 (90%) were seizure-free for more than two years, whereas other three cases were seizur-free for less than two yeasrs. Other epileptic seizures including grand mal were never seen at the time of follow-up.
2) Twenty-nine cases (97%) had normal I. Q. and only 1 case (3%) had mild retardation at the final examination.
3) Four types of the transformation of generalized spike--wave discharges during follow-up studies of the interictal EEG recordings in 30 cases were observed, i. e., (a) 3 c/sec spike-wave discharges subsequently disappeared (40%), (b) 3 c/sec spike-wave discharges were transformed into fast or irregular spike-wave paroxysms, afterward these patterns persisted or disappeared (47%), (c) 3 c/sec spike-wave discharges were still present (6.6%) and (d) fast or irregular spike-wave discharges persisted or disappeared (6.6%).
There was no significant difference in the mode of transformation of generalizedspikewave discharges, between male and female, between presence and absence of febrile convulsions or grand mal in past history, between early and late onset of typical absence, and between short and long duration of attack of typical absence.
