A clinical patho-anatomical study of clinically silent multiple sclerosis.

This is the first study on the frequency, size, number, and location of plaques in clinically silent MS. Among the present 18 patients in whom MS was unexpectedly diagnosed at autopsy, it had been clinically silent in 13. An estimate of the prevalence of silent MS is about 25% of that diagnosed in vivo. In the silent group, the MS plaques were located mainly in the periventricular areas, and this may explain the silent nature of the disease.