Dementia is a deterioration from a known or estimated prior level of intellectual function sufficient to interfere

broadly with the conduct of the patient's customary affairs of life, which is not isolated to a single narrow category of intellectual performance and which is independent of level of consciousness.

This deterioration should be supported by historical evidence and documented either by bedside mental status testing

or, ideally, by more detailed neuropsychological examination, using tests that are quantifiable and reproducible and for which normative data are available.

A. The criteria for the clinical diagnosis of probable ivd include all of the following:

1. Dementia

2. Evidence of two or more ischemic strokes by history, neurologic signs, and/or neuroimaging studies (CT of

T1- weighted MRI

B. The diagnosis of probable ivd is supported by:

1. Evidence of multiple infrared in brain regions known to affect cognition

2. A history of multiple transient ischemic attacks

3. History of vascular risk factors (e.g., hypertension, heart disease, diabetes mellitus)

4. Elevated Hachinski Ischemia Scale (original or modified version)

C. Clinical features that are thought to be associated with IVD but await further research include:

1. Relatively early appearance of gait disturbance

2. Periventricular and deep white-matter changes on T2-weighted MRI that are excessive for age

3. Focal changes in electrophysiologic studies (e.g., EEG, evoked potentials) or physiologic neuroimaging studies (e.g., SPECT-ET-NMR spectroscopy)

D. Other clinical features that do not constitute strong evidence either for or against a diagnosis of probable ivd

include:

1. Periods of slowly progressive symptoms

2. Illusions, psychosis, hallucinations, delusions

3. Seizures

E. Clinical features that cast doubt on a diagnosis of probable ivd include:

1. Transcortical sensory aphasia in the absence of corresponding focal lesions on neuroimaging studies

2. Absence of central neurologic symptoms/signs, other than cognitive disturbance

A clinical diagnosis of possible ivd may be made when there is:

1. Dementia

and one or more of the following:

2a. A history or evidence of a single stroke (but not multiple strokes) without a clearly documented temporal

relationship to the onset of dementia or

2b. Binswanger's syndrome (without multiple strokes) which includes all of the following:

i. Early-onset urinary incontinence not explained by urologic disease, or gait disturbance (e.g.,

parkinsonian, magnetic, apraxic, or "senile" gait) not explained by peripheral cause

ii. Vascular risk factors

iii Extensive white-matter changes on neuroimaging

Diagnosis of definite ivd requires histopathologic examination of the brain, as well as:

A. Chemical evidence of dementia

B. Pathologic confirmation of multiple infarcts, some outside of the cerebellum

A diagnosis of mixed dementia should be made in the presence of one or more other systemic or brain disorders

that are thought to be causally related to the dementia.

The degree of confidence in the diagnosis of IVD should be specified as possible, probably, or definite, and the other disorder(s) contributing to the dementia should be listed. For example: mixed dementia due to probable IVD and possible Alzheimer's disease, or mixed dementia due to definite IVD and hypothyroidism.