Subacute sclerosing panencephalitis as a cause of chronic dementia and relapsing brain disorder.

Two patients with subacute sclerosing panencephalitis (SSPE) are described because of the course of the disease, which is still thought to be unusual but might prove to be rather common. In both cases there was apparent recovery after about two years of illness. One of the patients had a relapse after eight years of remission and seems to have recovered also from this second period of illness, though with a more severe mental defect than after the first one. Thus, SSPE should be kept in mind as a possible aetiological factor in patients with a persisting slight to severe dementia after a brain disorder. Apparent recovery from SSPE does not exclude the possibility of relapse even many years later.