The Alzheimer myth and biomarker research in dementia.

The focus of most of the research on Alzheimer's disease in the last decades has been on senile plaques and neurofibrillary tangles. The vast majority of patients with Alzheimer's disease are over 75 years of age, whereas most of the research focuses on younger subjects. To consider old-age dementia as a homogenous well-defined condition ignores the complexity of this condition and limits the development of new diagnostic methods, preventive strategies, or treatment strategies that could be widely applicable in daily practice in the majority of the older patients. The current research on biomarkers focuses on correlates of plaques and tangles, which are poor markers in older dementia subjects. Acknowledging that dementia in old age is an essentially different condition from dementia at relatively younger age is needed and should lead to new approaches in dementia research.