Immediate changes of the electroencephalograms after intravenous injection of clonazepam and their relation to its effect on clinical fits in children with minor seizures.

Immediate EEG changes after intravenous administration of clonazepam and a correlation between the EEG changes and the effect of oral administration of the drug were studied in 21 children with minor seizures whose interictal EEG showed a paroxysmal abnormality. In 13 cases of infantile spasms whose EEG showed hypasrhythmia, paroxysmal discharges were completely or remarkably suppressed in 4 cases, partially suppressed in 3 cases, but not improved in 6 cases. Suppression bursts pattern was less improved. In 5 cases of Lennox syndrome, paroxysmal discharges were markedly improved in 3 cases. In a case of petit mal absence, parxoxysmal discharges were completely suppressed. In all 5 cases whose EEGs were completely improved, paroxysmal discharges reappeared 7 to 30 min after the intravenous injection. In 2 out of the 5 cases, paroxysmal discharges became severer at reappearance than before the injection. Among 12 cases whose EEG showed an improvement after the intravenous injection, their clinical seizures were improved in 9 cases, but the clinical effect was mostly transient. In the majority of the cases whose EEGs were not improved, no clinical effect was observed. There was a highly significant correlation between immediate EEG changes and clinical effect of clonazepam (p less than 0.02 by the chi-square test).