Electrophysiological and neuropsychological functions in patients treated with interferon-beta.

The neurotoxicity of interferon-beta (IFN-beta) was assessed by performing electrophysiological examinations and neuropsychological tests on 22 patients with malignant hematological diseases before, during, and after IFN-beta treatment. IFN-beta (6 x 10(6) IU/m2) was infused i.v. for 6 h daily for 7 days on alternate weeks for a total of three cycles (induction therapy) and was then continued at the same dose, twice a week, for an additional 24 weeks (maintenance therapy). Twenty-one of the 22 patients were evaluable. There were no significant changes in EEGs, visual evoked potentials, sensory conduction central time or motor nerve conduction velocity of two long nerves in the 15-19 patients studied before and after induction therapy, nor in the 6-8 patients investigated at the end of maintenance therapy. Neuropsychological monitoring failed to disclose any IFN-induced deterioration in 21 patients tested before and at the end of induction therapy or in the 10 patients who were also studied at the end of maintenance therapy. Despite certain limitations in the patient follow-up, the results underline the good general tolerance of IFN-beta.