Vascular Dementia

The differential diagnosis of VaDs include a number of conditions (see Table 3), but chiefly AD.

In consequence, the focus in a clinical diagnosis of AD has been on early episodic memory impairment, followed by often cognitive features, with a progressive course, with progressive dependence in function. This picture is distinct from early classical VaD.

Table 3 Differential diagnosis of vascular dementia SOURCE: Author

In its classical conceptual form, probable VaD is characterized by an abrupt onset, a fluctuating and stepwise course, signs of cerebrovascular disease and ischemic lesions on brain imaging. By contrast, AD is characterized by an insidious onset, progressive course, without clinical signs of CVD and without signs of CVD in brain imaging.

AD and CVD (Mixed dementia). The issue of mixed dementia is a challenge. Increasing evidence shows that different vascular factors are related to AD, and frequently CVD coexists with AD. This overlap is increasingly important in older populations. Clinical recognition of patients with mixed dementia or AD with CVD, however, is a problem. As detailed in the neuropathological series of Moroney et al., these patients have a clinical history and signs of CVD, being clinically closer to VaD. In fact, in this series, fluctuating course (OR 0.2) and history of strokes (OR 0.1) were the only items differentiating AD from the mixed cases.

Problematic clinical examples include stroke unmasking AD in patients with post-stroke dementia, insidious onset and/or slow progressive course in VaD patients, and cases where difficulty exists in assessing the role of less extensive WMLs or of distinct infarcts on neuroimaging. This clinical challenge may be solved when a sensitive and specific ante-mortal marker for AD is available, and the distinction between AD and VaD could be supported by more detailed knowledge on which site, type and extent of ischemic brain changes are critical for VaD and Table 4 Differential diagnosis between vascular dementia and Alzheimer’s disease. SOURCE: Author which extent and type of medial temporal lobe atrophy specifies AD.