Subacute sclerosing panencephalitis with atypical features.

The incidence of subacute sclerosing panencephalitis may be rising. This report describes three patients identified in New York City with atypical features including age of onset, prolonged prodrome, and lack of specific electroencephalographic changes. The diagnosis was confirmed with the identification of measles antibodies in the cerebrospinal fluid. Awareness of the possibility that the clinical presentation of subacute sclerosing panencephalitis may be changing may increase its timely diagnosis.