Etymology and meaning of the term "leukoaraiosis", as well as hypothetical mechanisms of the condition development are discussed. In the literature relations are reported between periventricular lesions of the white matter and arterial hypertension, arteriosclerosis, other vascular diseases, diabetes, etc. Moreover, relationship between leukoaraiosis and the Alzheimer disease has been investigated. The pathogenesis of leukoaraiosis is not quite clear yet, nevertheless, pathology of small vessels penetrating deep into the white matter of the cerebral hemispheres is considered to be an important etiological factor in the disease. Some research findings reported in the literature indicate marked cognitive deficits in patient with MRI changes typical of leukoaraiosis. Reduced dynamics and drive, characteristic of the frontal lobe dysfunction, seem to predominate in the clinical pattern of leukoaraiosis.