The clinical diagnosis of vascular dementia: A comparison among four classification systems and a proposal for a new paradigm.

Throughout the 1990s a variety of schemes for the diagnosis of Vascular Dementia (VaD) were proposed, including the ADDTC criteria for Ischemic Vascular Dementia, the NINDS-AIREN criteria for Vascular Dementia, Bennett's criteria for Binswanger's disease, and the ICD-10 criteria for Vascular Dementia. We undertook a retrospective analysis of a series of ambulatory outpatients with dementia to determine the prevalence with which patients were diagnosed by each of these diagnostic schemes, and to survey the clinical characteristics associated with VaD. We found that the diagnostic schemes for VaD were not interchangeable; patients diagnosed with VaD using one set of criteria were not necessarily diagnosed with VaD using other criteria. The most common clinical characteristics associated with VaD, regardless of the diagnostic scheme that was used, were hypertension, extensive periventricular and deep white matter alterations on MRI (leukoaraiosis), and differential impairment on neuropsychological tests that assess the ability to establish/maintain mental set and visuoconstruction, with relatively higher scores on tests of delayed recognition memory. Interestingly, the majority of VaD patients obtained low scores on the Modified Ischemic Scale, since cortical infarcts and a history of a sudden onset and/or step-wise decline in cognitive function were rare. We conclude that the current diagnostic schemes for VaD do not necessarily consider the heterogeneous nature of VaD. A new paradigm that seeks to describe, in addition to diagnosing dementia associated with cerebrovascular disease is discussed.

Computer-mediated measurement and subjective ratings of white matter hyperintensities in vascular dementia: relationships to neuropsychological performance.

White matter hyperintensities (WMHs) are frequently found on MRI studies of vascular dementia (VaD) patients. As several studies have demonstrated that WMHs are often associated with severity of illness, cognitive impairment, and functional decline, the accurate and reliable measurement of WMHs on MRI is an important, yet often overlooked, prerequisite for accurate interpretation of neuroimaging studies. Using a sample of 39 VaD patients, we evaluated the reliability and validity of a visual ordinal rating scale and a computer-mediated thresholding technique to evaluate WMHs. Results indicated the computer-mediated technique had slightly stronger inter-rater reliability than the visual ordinal rating scale. Furthermore, the computer-mediated thresholding technique was correlated with measures of neuropsychological functioning believed to be compromised in VaD (i.e., psychomotor speed, executive functioning) while the visual rating scale was not. Results suggest that this computer-mediated thresholding technique is superior to visual ratings of WMHs.

From Binswanger's disease to leuokoaraiosis: what we have learned about subcortical vascular dementia.

The literature regarding subcortical vascular dementia associated with periventricular and deep white matter alterations is reviewed. Information pertaining to neuropathological, neuropsychological, and neuroradiological studies is emphasized. Based on this review and prior neuropsychological studies associating subcortical vascular pathology with greater deficits on tests of executive dysfunction and with relatively better performance on tests of delayed recognition memory, we conclude that vascular dementia associated with periventricular and deep white matter alterations can and should be regarded as a subcortical dementing illness. Also, we support schemes suggested by Erkinjuntti et al. (2000) and Cosentino et al. (this issue) that attempt to integrate neuropsychological and neuroradiological data into a diagnostic paradigm that describes, as well as diagnoses, dementing disorders. We discuss questions and issues about vascular dementia that deserve further consideration and study.