[Towards a reliable prognosis for multiple sclerosis]

Although the general course of multiple sclerosis is well known from natural history studies, the determination of a detailed prognosis in a given individual is almost an insurmountable task. Cerebral magnetic resonance imaging is the best predictor of conversion to definite multiple sclerosis after a first demyelinating event. The main factors indicative of long-term bad prognosis are: onset after the age of 40, initial pyramidal or cerebellar signs, high relapse rate during the first two years, and onset of the progressive phase. Altogether, up to 20% of patients have a benign course.