Initial electroencephalographic findings in children with acute lymphoblastic leukaemia

Electroencephalography (EEG) was performed on 66 children with acute lymphoblastic leukaemia, 45 before treatment and 21 during the first 5 days of chemotherapy. The patients, aged 7 months to 16 years, 33 boys and 33 girls, had been admitted to the Department of Paediatrics, University of Oulu, between March 1976 and January 1987. The EEG findings were compared with those in 66 age and sex-matched control children chosen at random from the local population. The patients had significantly more frequent and more severe disturbances in background activity (p less than 0.001) than the controls and increased slow waves in the occipital (p less than 0.001) and temporal regions (p less than 0.01). The patients who had received chemotherapy before the EEG recording had EEG disturbances significantly more frequently than the other patients (p less than 0.01), but the latter still had EEG abnormalities significantly more frequently than their matched controls, although they did not have severe changes (grade 3). The results suggest that chemotherapy increases EEG changes during the early days of induction therapy and possibly induces long-term disturbances in brain function. The associations between EEG changes and clinical findings were also analysed and the results show that a long duration of leukaemic symptoms or an aggressive disease may lead to EEG abnormalities.