CLINICAL AND ELECTROENCEPHALOGRAPHIC CORRELATES IN RASMUSSENS ENCEPHALITIS

Purpose: Rasmussen's encephalitis (RE) is a progressive childhood dise ase characterized by unilateral brain dysfunction, seizures, and infla mmatory histopathology. Converging lines of evidence suggest that an a utoimmune process is important in the pathogenesis of RE. Methods: Two patients with pathologically confirmed RE and increased levels of cir culating glutamate receptor subunit (GluR3) antibodies were studied pr ospectively before, during, and after trials of plasmapheresis (PEX) a nd other immunomodulation. Frequency, duration, and intensity of clini cal seizures were directly correlated with the abundance of interictal epileptiform activity on serial EEGs. Results: Serial EEGs in these p atients suggest that early in the course of RE interictal epileptiform activity is localized to the affected hemisphere and that disease pro gression is associated with increasingly frequent bilaterally synchron ous and contralateral epileptiform activity, Conclusions: The clinical and EEG parameters of epileptogenesis were transiently diminished by PEX, which suggests that circulating factors induce dose-dependent, re versible epileptogenic effects in some patients with RE.