Blinded, prospective, and serial evaluation by quantitative-EEG in interferon-alpha-treated hepatitis-C

Objectives - To estimate the effect of brain function due to IFN-alpha in c hronic hepatitis C patients by the quantitative EEG. Methods - 56 chronic h epatitis C patients were administered IFN-alpha intramuscularly at 9x10(6) IU daily for the first 4 weeks and then 3 times/week for the next 20 weeks. Serial EEGs were obtained in each subject before, at 2 and 4 weeks, and af ter completing the treatment. Resting EEG without artifacts was selected fo r quantitative EEG analysis, which was performed blindly. The frequency ran ge was divided into delta to beta. The absolute and relative powers of each frequency band in each subject were calculated and the differences of thes e powers at different stages were analyzed statistically. Results - The abs olute powers of slow waves (delta, theta 1, and theta 2) increased while al pha 2 and fast wave (beta) decreased significantly at all locations during IFN-alpha administration. The total power and alpha 1 values revealed no si gnificant alterations. The relative power revealed the same alteration duri ng treatment. These changes disappeared following the treatment. Such diffu se slowing in the EEG was revealed by the total change in the whole subject s. Conclusions - Diffuse slowing in the EEG was induced by IFN-alpha, was r eversible, and was evident as the total change in the subjects. These findi ngs suggested mild IFN-alpha-induced encephalopathy.