Cognitive impairment (CI) associated with brain aging is a consequence of disorders varying in etiology and pathogenesis, which often coexist in elderly patients and can have a mutual impact on the clinical manifestation, severity, and rate of progression of CI. Alzheimer's disease (AD) and vascular CI are the most common forms of dementia in the elderly. In recent decades, there has been increasing evidence that there is a close relationship between these forms due to a substantial overlap of their risk factors, clinical manifestations, neuromorphological changes, as well as genetic and neuroimaging biomarkers. The complex multicomponent relationship of these disorders also makes it difficult to elaborate effective preventive and therapeutic approaches in these patients.