Prolonged and atypical course in some cases of subacute sclerosing panencephalitis.

Subacute sclerosing panencephalitis (SSPE) is a persistent viral infection of the central nervous system due to a defective measles virus. Beginning with progressive cognitive malfunctioning, myoclonus and other less specific neurologic signs and symptoms, it usually evolves to a vegetative, decorticated state and death. Disease course and characteristics can be highly variable. Since the widespread measles vaccination in the Western countries started in the late seventies and early eighties, the incidence of SSPE has dropped significantly. Also adult onset is more frequently seen which changes the field of differential diagnosis. In this article 3 atypical cases of SSPE are described with peculiarities such as adult onset, pronounced extrapyramidal involvement, remission and prolonged disease course. Common features of the disease are emphasized to enable accurate diagnosis which is based on clinical features, presence of high titers of serum and cerebrospinal fluid (CSE) measles antibodies, MRI and EEG.