[Gray matter lesions and cognitive impairment in multiple sclerosis].

Multiple sclerosis (MS) has long been considered to be the autoimmune disease that primarily affects oligodendrocyte and myelin in the white matter (WM) of the CNS. However, renewed interest in the gray matter (GM) pathology including cortical and deep GM of MS is emerging. Radiological and pathological assessments demonstrate that substantial cortical demyelination is prominent in all stages or courses of MS, and cortical neurodegeneration is also present in even normal-appearing GM in MS. Patients with MS have cognitive impairment as represented by the latent start of impairment from the very early stage of the disease course, and not only WM lesions but also GM lesions might be good predictors for cognitive impairment in MS. Although the cause of the GM lesions in MS has not been fully determined, an increase in knowledge of the structure of GM lesions in MS brains will result in more targeted therapeutic approaches to the disease.