Reclassification of the Vascular Dementias: Comparisons of Infarct and Noninfarct Vascular Dementias

Abstract

This article focuses on some of the long-standing problems that exist in the classification of the vascular dementia. To clarify the definition of vasculardementia, mental statusandother cognitive processes were investigated in 12 patients with a single cerebral infarct (mean age, 74.8 years), 17 patients with multiple cerebral infarcts (mean age, 71.4 years), 21 vascular patients with no cerebral infarcts (mean age, 76.9 years), and 16 demographically equivalent normal elderly persons (mean age, 70.4 years). The following null hypotheses/ hypotheses were tested: (a) The cognitive impairment of single-infarct, multipleinfarct, and noninfarct vascular patients is nodis significantly greater than and outside the range of that in normal aging, and (b) there are/are not significant differences between single-infarct, multiple-infarct, and noninfarct vascular patients on mental status and other cognitive measures. Measures used included the Mini-Mental State Examination, Dementia Rating Scale, Western Aphasia Battery, and Boston Naming Test. Results indicate that vascular disorders involve a decrement in mental status and other cognitive functions that is significantly greater than the age-associated cognitive impairment of normal aging. Also, results from the study indicate that there were no robust, reliable significant differences between single-infarct, multiple-infarct, and noninfarct patients. The validity of the distinction of focal versus generalized or diffuse cerebral lesions is questioned. The nosologic entity of noninfarct vascular dementia is introduced. The future nosology of vascular dementia should provide for noninfarct vascular dementia, defined as vascular dementia caused by underlying vascular mechanisms other than cerebral infarction.

Interface between Vascular Dementia and Alzheimer Syndrome: Nosologic Redefinition

“…Our data point to the idea that multiinfarct dementia is only one subtype of vascular dementia, although possibly the most prevalent one, and that vascular dementia is broader than multiinfarct dementia 1–3. Further, our data will suggest that the nosologic entity of vascular dementia must be extended beyond the infarct concept, because there appear to exist noninfarct vascular dementing conditions 1–3. Vascular dementia is redefined to include a new category of vascular dementia, which we have termed noninfarct vascular dementia 1–3,22.…”

“…In this paper the construct of vascular dementia is reconceptualized and broadened to include what we term “noninfarct vascular dementia.”1–3 How vascular dementia is defined is critical for understanding clinicopathophysiological features of the syndrome. Definition, nomology, and nosology are crucial methodological components for understanding mechanisms underlying vascular dementia 4.…”

“…To be more specific, in analyzing the evolution of the construct of vascular dementia during the 20th century, one sees that during the mid‐1900s the term vascular dementia was equated with arteriosclerotic psychosis or cerebral arteriosclerosis 9,10. Following this, there has been an equation between vascular dementia and multiinfarct dementia for the past 25 years 1,2,11–14. These two terms became virtually synonymous, and this equation between vascular dementia and multiinfarct dementia has been reflected in formal classification 15–19.…”

“…We will suggest that the construct validity 2,4,20,21 of vascular dementia would have been better served had multiinfarct dementia been conceptualized as an additional subtype of vascular dementia rather than as a replacement for all previous subtypes. Our data point to the idea that multiinfarct dementia is only one subtype of vascular dementia, although possibly the most prevalent one, and that vascular dementia is broader than multiinfarct dementia 1–3. Further, our data will suggest that the nosologic entity of vascular dementia must be extended beyond the infarct concept, because there appear to exist noninfarct vascular dementing conditions 1–3.…”

General Intellectual Decline and Daily Living Skills

“…Individuals were excluded from data analyses if there was a history of stroke causing a hemispheric syndrome affecting test taking (e.g., aphasia, hemiparesis, hemi-spatial neglect). Individuals without evidence of infarcts had a clinical history and neuroimaging findings consistent with those of patients classified as non-infarct vascular dementia by Emery, Gillie, and Smith (1996). They had a range of cardiovascular disorders and other risk factors for stroke (e.g., diabetes), as well as MRI evidence of small vessel ischemia and/or ischemic features from the Hachinski scale such as hypertension, fluctuating disease course, atherosclerosis, and relative preservation of personality.…”