c p S t 1 b n b d d t This review paper raised important controversies in the eld of vascular cognitive impairment. The notion that erebrovascular disease (CVD) can cause cognitive deficits as been recognized in the literature for several centuries 1]. However, as noted by Dr. Chui, the diagnosis of vasular dementia (VaD) remains problematic. Although we ave multiple clinical criteria oriented to diagnose VaD vailable to us [2–6], the phenotype still remains elusive 7,8]. This is, in part, caused by 2 important factors. The rst concerns the heterogeneity of the CVD. VaD can deelop after a single ischemic lesion or after multiple lesions, r some patients can manifest progressive cognitive decline ssociated with multiple “silent” ischemic lesions [9,10]. he second relates to the concomitant manifestation of lzheimer’s disease (AD) and CVD. Because AD is the ost frequent form of dementia in the elderly and can oexist with severe CVD, it is difficult to determine whether he cognitive deterioration is solely consequence of vascular actors or to underlying AD. There have been significant linical, pathologic, and radiologic advances in this field ver the last decade that can help clarify its most controersial aspects. Nevertheless, there is still a need to solve ome basic issues before we move forward in the study of he relationship between AD and vascular disease and the isk factors associated with both diseases. The different definitions of dementia used by current linical criteria are a critical aspect that warrants discusion before we can move to more elaborated descriptions f vascular cognitive impairment syndromes. The Naional Institute of Mental and Neurological Disorders and he Association Internationale pour la Researche et ’Enseigment en Neurosciences (NINDS-AIREN) [3], the iagnostic and Statistical Manual of Mental Disorders, 4th dition (DSM-IV) [4], and the International Classification f Diseases, 10th Edition (ICD-10) [6] criteria for VaD ased their definition of dementia on the fact that memory eficits must be present. However, cerebral infarcts can ccur in any brain territory and do not always affect memory-