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The field of Alzheimer dementia has a problem of nomeclature. When somebody says Alzheimer dementia or disease they may be refering to three different entities: the clinical disease, the pathological diagnosis, or amnestic dementias in the elderly. In a recente review the authors did not quite understand where this problem arose.
Knopman, Petersen and Jack. Neurology 2019, 92:1053-1059
The main reason for the nosologiocal confusion may be political. Americans prefer to think that they discovered everything. In fact the population in general and neurologists especially traditionally thought that dementias of the elderly were due to vascular disease. This was the neurological and popular concept for at least a few centuries, until the group of John Marshall in London identified the criteria for the diagnosis of vascular dementia.
Harrison MJ, Thomas DJ, Du Boulay GH, Marshall J. Multi-infarct dementia. J Neurol Sci. 1979 Feb;40(2-3):97-103.
They described this very clearly from a clinical and radiological point of view, very soon after the first CT scans became available, exactly at Queen Square.
Radue EW, du Boulay GH, Harrison MJ, Thomas DJ. Comparison of angiographic and CT findings between patients with multi-infarct dementia and those with dementia due to primary neuronal degeneration. Neuroradiology. 1978;16:113-5.
The problem was their scientific purity, which made them call the other patients, those that were not vascular, by a name that did not involve the pathological diagnosis, i.e., primary degenerative dementia. This atitude may have been political too. As the British had been involved in the Great War, they may have been reluctant to use German names in fear that the data may have been aquired in unethical studies. And they had their own internal politics at the National Hospital, Queen Square. Locally there no interest in John Marshall becoming an international celebrity. Whatever the reason was, the fact that Alzheimer is not in the title of these papers made them be forgotten.
But soon the Scandinavians used these data to develop a framework of diagnosis of what they called pressenile dementia, which, as Marshall and colleagues had already demonstrated, accounted for 60% of the dementias of the elderly.
Gustafson L, Nilsson L. Differential diagnosis of presenile dementia on clinical grounds. Acta Psychiatr Scand. 1982 Mar;65(3):194-209.
The Scandinavians looked at fifty-seven patients with three rating-scales were for identification of Alzheimer’s disease, Pick’s disease and multi-infarct dementia. The ischaemic rating-scale consisted of abrupt onset, stepwise progression, fluctuating course, history of stroke. The rating-scale for diagnosis of Alzheimer dementia contained early spatial disorientation, apraxia, aphasia, agnosia, logoclonia and increased muscular tension. Thus were established the criteria for the diagnosis os “Probable Alzheimer” which were to be included in a consensus publication of the NINCDS in 1984, incorporated in DSM-III in 1986, and used world-wide since then to indicate the progressive amnestic dementia patients. Including in Brazil.
M, Treves TA, Korczyn AD. DSM-III-R criteria for primary degenerative dementia and multi-infarct dementia [corrected]. Alzheimer Dis Assoc Disord. 1992 Summer;6(2):111-8. Erratum in Alzheimer Dis Assoc Disord 1993 Summer;7(2):128.
Since then there has been enormous progress in the field of Alzheimer dementia. Criteria have been developed and used widely for the diagnosis of mild cognitive impairment, the visual variant with posterior cortical atrophy; the logopenic variant with speech impairment; and the disexecutive syndrome. In all there is clinicopathological correlation with neuritic plaques and neurofibrillary tangles.
In the past 10 years the antemortem diagnosis by amyloid PET scans and neurofibrillary tau biomarkers in the cerebrospinal fluid has come into clinical practice. A new problem arose, in that many cognitively normal elderly people have not only these indicators of pathological Alzheimer dementia, but also have indicators of other pathology as hippocampal atrophy and vascular disease. As dementia develops, it is the interaction of many etiologies that drives the clinical course.
Dr Paulo Bittencourt