Is Dementia a Disease?

Abstract

Background: It is customary for many neurologists to think that dementia is a disease. This view is based on the following reasons: (1) a brain disease is the cause of cognitive impairment; (2) therefore, such cognitive impairment is substituted for the disease, becoming dementia, which is then also regarded as a mental disease. Objective: In this brief article, I take exception to such a view, contrary to the common belief in the medical field, on the ground that senile plaques and/or neurofibrillary tangles or any other factors cause neuronal apoptosis but they do not cause dementia directly. Methods: Literature on dementia and aphasia are critically and briefly reviewed to get the historical perspective that it is the progressive neuronal losses, losing brain functions as a result, that cause dementia; that is, brain diseases cause neuronal losses which then result in the decrease of brain functions, thereby leading to dementia. Results: There is no direct cause-effect relationship between brain disease, be it caused by vascular factors or not, and dementia which is the consequence or sequela of neuronal losses. Conclusions: It is concluded that dementia is not a disease and yet it occurs not only in Parkinson’s disease, Alzheimer’s disease (AD), Huntington’s disease and Pick’s disease, but also in any other neurodegenerative disease, e.g., spinocerebellar ataxia, or vascular disease, e.g., Binswanger’s disease, as part of the process of aging; in fact, AD is now regarded by some as a vascular disorder with neurodegenerative consequence, rather than a neurodegenerative disorder with vascular consequence. But vascular disorder is misleading if AD includes both neurofibrillary tangles and senile plaques; on the other hand, AD cannot be a vascular disorder if it includes only neurofibrillary tangles, as it should. Dementia, in this context, is re-defined as the differential manifestation of deteriorating brain functions over time as a part of aging due to cell deaths in the brain caused by any neurodegenerative disease. Its prominent symptoms are language disorders which must be distinguished from aphasias. It is also suggested that in fairness to Fischer, senile plaques be designated as Fischer’s disease separate from neurofibrillary tangles for which AD was originally named as an eponym.

Serum N-glycan profile shift during human ageing

“…Dementia encompasses deteriorations in several cognitive domains (Morris, 2005). It has been defined as a manifestation of deteriorating brain functions over time as a part of ageing due to death or functional decline of brain cells caused by neurodegeneration or other disease (Peng, 2003). Alzheimer's disease (AD), the most common type of dementia, is a progressive, degenerative brain disease accounting for 65-70% of all dementia cases (Blennow et al, 2006).…”

Automated CT-based segmentation and quantification of total intracranial volume

“…Consequences from suffering biological and cognitive degeneration include frailty, weakness, shortened life expectancy and loss of independence. Dementia can be defined as an acquired syndrome producing brain dysfunction (cognitive impairment, deterioration of intellect and personality changes) as part of aging due to cell death caused by brain disease [3]. The most common cause of dementia is Alzheimer's disease (AD), followed by vascular dementia, Lewy body dementia, frontotemporal dementia and Parkinson's disease.…”

Neuropathology of Dementia Disorders

“…Previously defined as the manifestation of deteriorating brain functions over time due to cell deaths in the brain caused by neurodegeneration or any other disease [3], according to recent research dementia is not primarily caused by neuronal cell death/loss, but by dysfunction and loss of synapses [4] in AD [5] and in α-synucleinopathies [6]. Other causes include cholinergic neuronal and axonal abnormalities [7,8], as well as pre-and postsynaptic cortical cholinergic deficits also occurring in early AD [9].…”