The mystery of electroencephalography in acute lymphoblastic leukemia.

The aim of the study was to evaluate changes in electroencephalogram (EEG) recordings during the course of acute lymphoblastic leukemia (ALL) in children. The study group consisted of 48 children with ALL who underwent a total of 72 EEGs at various stages of the disease. The medical files were reviewed for pertinent clinical data, and the EEGs were evaluated for changes in brain activity. Abnormal background activity was noted in 52.2% of the EEGs done at 1-10 days of therapy, in 43.5% of those done at 10-60 days, and only 4.3% of those done at later stages (p=0.037). These findings, together with earlier reports, suggest that early-stage ALL, even before treatment, may be associated with excessive slow EEG activity, which improves over time. The EEG changes, by themselves, are not an indication of central nervous system leukemia or a predictor of later seizures or other central nervous system involvement.