[Spectral EEG analysis in children treated with high-dose methotrexate].

During the use of a therapeutic regimen of high-dose methotrexate (HD-MTX) with leucovorin rescue in two cases of osteogenic sarcoma and malignant lymphoma without central nervous system (CNS) involvement, serial EEG monitoring before and after MTX infusion was performed with special reference to occipital basic activity. The EEGs were analyzed as to the power average spectrum using an ATAC-450 (NIHON KOHDEN). At 48 hours after the initiation of MTX, there was a transient but statistically significant slowing, such as a drop in the dominant frequency and a decrease in the alpha/theta ratio. Complete recovery of EEG changes occurred within one week. No clinical symptoms suggestive of CNS impairment were noted in either case. These data suggest that EEG alterations might be a reflection of subclinical CNS impairment. Therefore, serial EEGs might be a good early indicator for the detection of leukoencephalopathy in high-risk patients.