Clinical significance of white matter changes.

Although their clinical significance has long been debated, it has now been well established, both from cross-sectional and longitudinal studies, that white matter lesions on magnetic resonance imaging are associated with a number of adverse outcomes, including cognitive impairment, functional disability, death, neurologic problems, and depression. Novel imaging methods now allow testing of models of the pathogenesis of such lesions, which will open new avenues for therapeutic intervention to try to prevent or delay the developments of such changes.