Mohammed T. Abou-Saleh

Principles and Practice of Geriatric Psychiatry.Editors: Professor John R. M. Copeland, Dr Mohammed T. Abou-Saleh and Professor Dan G. BlazerCopyright & 2002 John Wiley & Sons LtdPrint ISBN 0-471-98197-4 Online ISBN 0-470-84641-0PATHOLOGY OF VASCULAR DEMENTIA 249International Criteria for Vascular Dementia and Their Problems:ICD-10, DSM-IV, ADDTC and NINDS-AIRENJohn V. Bowler 1 and V. Hachinski 21 Royal Free Hospital, London, UK and 2 University of Western Ontario, London, CanadaThere are two sets of criteria currently available for the diagnosisof vascular dementia. The Diagnostic and Statistical Manual ofMental Disorders, 4th edn (DSM-IV) 1 and the Classification ofMental and Behavioural Disorders, 10th Revision (ICD-10) 2 aregeneral diagnostic tools and outline the criteria but do notoperationalize them. The second set, the State of CaliforniaAlzheimer’s Disease Diagnostic and Treatment Centers 3 and theNational Institute of Neurological Disorders and Stroke and theAssociation Internationale pour la Recherche at L’Enseignementen Neurosciences (NINDS–AIREN) 4 criteria, are developmentsof the first two and offer operational criteria.There are three fundamental flaws and several lesser errors lyingin the details of these criteria. All the criteria are fundamentallysimilar in that they first require the presence of dementia, which isbased on Alzheimer’s disease (AD)-type features, and subsequentlyidentify vascular dementia as a subset of all dementia,using vascular features that are often operationalized using theischaemic score 5 .Unfortunately, the use of Alzheimer-based criteria for thediagnosis of dementia has now been clearly shown to be wrong.Vascular dementia does not closely resemble AD, even whenAlzheimer-based criteria have been used for case identification 6 .Thus, cases selected using current criteria represent only a subsetof all vascular dementia. This is the first major flaw in the currentcriteria.The second problem is the increasing recognition of mixeddementia. Originally, vascular dementia and AD were separatedby the presence of large infarct volumes 7 . In the nun study, inwhich 47% of demented patients had mixed disease, very smallamounts of cerebrovascular disease profoundly altered the age ofpresentation and speed of progression of what otherwise appearedto be AD 8 . Reclassification of autopsy data to allow small infarctvolumes to convert a diagnosis of AD to mixed dementiaincreased the proportion of cases with mixed dementia from 2%to 18% 9 . Thus, mixed dementia is far more important than wasrealized when the current criteria, which scarcely recognize mixeddisease, were prepared. No good method yet exists for separatingmixed dementia. Criteria that first select cases that appear like ADand then subselect those with vascular features might form anexcellent basis for doing so; unfortunately, this is what the currentcriteria for vascular dementia do and it is very likely that much ofthe reported data about vascular dementia is in fact about mixeddisease.The next fault is the level of severity. The criteria definedementia as the level of cognitive impairment at which normaldaily functions are impaired, and therefore will identify only latecases, underestimating the prevalence of cognitive impairment dueto vascular disease. More importantly, they prevent identificationof early cases that would benefit most from preventativetreatment 14 . This important early stage has been termed ‘‘vascularcognitive impairment’’ (VCI) 10 . VCI is important because vasculardisease is the largest single identifiable risk factor for dementiaapart from age, and the only one currently treatable.The above features constitute the fundamental faults of thecurrent criteria. There are a number of additional problems thatlie in their details. Differences in the details lead to greatdifferences in the proportion of cases identified as having vasculardementia 3 .Correction of these faults requires wholesale revision of thecriteria with the development of new criteria based on data ratherthan supposition 11–13 .REFERENCES1. American Psychiatric Association. Diagnostic and Statistical Manualof Mental Disorders, 4th edn. Washington, DC: American PsychiatricAssociation, 1994.2. World Health Organization. The ICD-10 Classification of Mental andBehavioural Disorders. Diagnostic Criteria for Research. Geneva:World Health Organization, 1993.3. Chui HC, Victoroff JI, Margolin D et al. Criteria for the diagnosis ofischemic vascular dementia proposed by the State of CaliforniaAlzheimer’s Disease Diagnostic and Treatment Centers. Neurology1992; 42: 473–80.4. Roman GC, Tatemichi TK, Erkinjuntti T et al. Vascular dementia:diagnostic criteria for research studies. Report of the NINDS–AIREN international workshop. Neurology 1993; 43: 250–60.5. Hachinski VC, Iliff LD, Zilkha E et al. Cerebral blood flow indementia. Arch Neurol 1975; 32: 632–7.6. Bowler JV, Hachinski VC. Vascular dementia. In Feinberg TE, FarahM, eds, Behavioral Neurology and Neuropsychology. New York:McGraw-Hill, 1997, 589–603.7. Tomlinson BE, Blessed G, Roth M. Observations on the brains ofdemented old people. J Neurol Sci 1970; 11: 205–42.8. Snowdon DA, Greiner LH, Mortimer JA et al. Brain infarction andthe clinical expression of Alzheimer disease. The nun study. JAmMed Assoc 1997; 227: 813–17.9. Bowler JV, Munoz DG, Merskey H, Hachinski VC. Fallacies in thepathological confirmation of the diagnosis of Alzheimer’s disease. JNeurol Neurosurg Psychiat 1998; 64: 18–24.10. Hachinski VC, Bowler J. Vascular dementia. Neurology 1993; 43:2159–60.11. Bowler JV, Hachinski V. Criteria for vascular dementia: replacingdogma with data. Arch Neurol (2000b, in press).12. Bowler JV. Vascular dementia: changing concepts and criteria. 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