Abstract
A case is reported of a boy who at the age of 14 years developed subacute sclerosing panencephalitis. He deteriorated over a period of 9 months, improved greatly and remained stable for 7 years before relapse. The final deterioration to death extended over 6 years. During the whole period he was examined regularly and the electroencephalogram recorded at 3 to 6 monthly intervals. The brain was examined histologically after death. Electroencephalographic and pathological features are described.