A case of subacute sclerosing encephalitis in a child, aged 3 years 6 months, who had contracted measles from his mother on day 27 as a neonate, is reported from Akita University School of Medicine, Japan. He presented with acute cerebellar ataxia which gradually improved, but mental deterioration and head nodding developed. The EEG showed diffuse slowing and periodic discharges that synchronized with the nodding. Measles antibody titers in the CSF and serum were abnormally elevated. MRI showed diffuse high intensity T2-weighted images in the white matter. Treatment with oral isoprinosine and intraventricular interferon failed to stem the relentless progression to a bedridden, mute stage within 3 months. This was followed by a plateau and later, a gradual but limited clinical improvement and MRI evidence of progressive cerebral atrophy. 
COMMENT. Measles virus infection under 1 year of age is a risk factor of SSPE. Immaturity of the brain at the time of measles infection may predispose to the SSPE.