SSPE is a rare complication of

(B) Measles # SSPE: It is characterized by a history of primary measles infection usually before the age of 2 years, followed by several asymptomatic years (6-15 on average), and then gradual, progressive psychoneurological deterioration, consisting of personality change, seizures, myoclonus, ataxia, photosensitivity, ocular abnormalities, spasticity, and coma.> Pathologic changes are firstly observed in the white matter of the hemisphere.