Computerized evaluation of electroencephalographic changes accompanying exchange transfusion in Reye's syndrome

The EEGs of 7 children with Reye's syndrome (fatty liver and encephalopathy) were continuously recorded on magnetic tape for times ranging from 12 to 80 h. During these times the major therapy consisted of exchange blood transfusions. The tapes were automatically processed on a LINC-8 computer using a peak-detection algorithm. The main parameters investigated were the delta and theta indices, the mean EEG frequency, the mean peak-to-peak amplitude, and the frequency versus amplitude characteristics of the delta waves. In 5 patients who responded to therapy, a marked decrease in the delta activity and an increase in mean frequency were noted subsequent to exchange transfusions. In all 5 cases the delta waves exhibited a similar pattern of decreasing amplitude and increasing frequency following therapy. However, in 2 patients with a fatal outcome, no favorable EEG response was observed during treatment, and a simultaneous decline in both delta frequency and delta amplitude was noted as the clinical condition worsened. The results of this study indicate that continuous EEG monitoring in Reye's syndrome may be an important clinical adjunct in evaluating the effectiveness of exchange transfusion therapy and in signaling the need for further treatment.