Abstract
We examined the somnolence syndrome, which is one of the side effects of cranial irradiation. Out of 53 patients in acute leukemia who had received cranial irradiation, nine patients (17%) developed the somnolence syndrome. Patients with the somnolence syndrome showed slow waves on EEG. Some patients had ventricular dilatation and widening of sulci before cranial irradiation on CT findings, but these findings improved after cranial irradiation. Out of nine cases with the somnolence syndrome, 6 patients survived and did not experience difficulties in school. But one patient showed calcification on CT brain scan. It is considered that the cause of the somnolence syndrome is a trasient inhibition of myelin synthesis and most patients improved without serious sequelae. It is necessary to follow up many cases of somnolence syndrome.
