Sequential quantitative EEG analysis in acute lymphocytic leukemia of children.

Potential brain toxicity is a major concern in the treatment of acute lymphocytic leukemia with cranial irradiation or intrathecal methotrexate. We used quantitative EEG analysis based on the Fourier transform to study 13 children at the time of diagnosis, after induction, and following consolidation which included extended intrathecal chemotherapy. None had detectable CNS infiltration by leukemia. Nonetheless, initial EEG frequencies were markedly depressed compared to expected values for age (p less than .001), and improved dramatically after induction (p less than .001). Following consolidation, EEG frequencies remained significantly lower than predicted from a control population (p less than .05). Quantitative EEG is a sensitive procedure that appears useful in assessing subtle neurologic effects of acute leukemia and its treatment.