Alzheimer’s disease is characterized by the abnormal accumulation and spread of the tau protein in the brain.
In a new study from McGill University, researchers found how tau spreads according to four distinct patterns that lead to different symptoms with different prognoses of the affected individuals.
These findings indicate that tau pathology in the brain varies according to at least four distinct patterns. This would suggest that Alzheimer’s is an even more heterogeneous disease than previously thought.
The spread of tau in the cerebral cortex is a key marker for Alzheimer’s.
In recent years, it has become possible to monitor the accumulation of the toxic protein in the brain of Alzheimer’s patients with the help of PET technology, an advanced medical imaging technique.
For the past thirty years, many researchers have described the development of tau pathology in Alzheimer’s using a single model, despite recurring cases that do not fit that model.
However, the current findings explain why different patients may develop different symptoms.
In the study, the team examined people who had not yet developed any symptoms, so-called pre-symptomatic Alzheimer’s, participants with mild memory difficulties and those with fully developed Alzheimer’s dementia.
The team identified four clear patterns of tau pathology that became distinct over time.
The prevalence of the subgroups varied between 18% and 30%, which means that all these variants of Alzheimer’s are actually quite common and no single one dominates.
Variant one: Tau spreads mainly within the temporal lobe and primarily affects memory. Variant one occurred in 33% of all cases.
Variant two: In contrast to variant one, this variant spreads in the rest of the cerebral cortex.
The individual has fewer memory problems than in the first variant, but on the other hand has greater difficulties with executive functions, that is, the ability to plan and perform an action. Variant two occurred in 18 percent of all cases.
Variant three: The accumulation of tau takes place in the visual cortex, i.e. in the part of the cerebrum where information from the optic nerve is processed and classified.
The visuospatial processing of sensory impressions in the brain is affected in individuals with this pattern.
They have difficulty orienting themselves, distinguishing shapes and contours, distance, movement and the location of objects in relation to other objects. Variant three occurred in 30% of all cases.
Variant four: Tau spreads asymmetrically in the left hemisphere and primarily affects the individual’s language ability. Variant four occurred in 19% of all cases.
The researchers believe that this new knowledge can give patients more individualized treatment methods in the future.
If you care about Alzheimer’s disease, please read studies about a new way to predict Alzheimer’s disease-like memory loss before it strikes and findings of diet high in this nutrient may help fight against Alzheimer’s disease.
For more information about dementia treatment and prevention, please see recent studies about a new way to accurately detect Alzheimer’s disease and results showing that these personality traits may help prevent Alzheimer’s disease.
The study is published in Nature Medicine. One author of the study is Jacob Vo-gel.
Copyright © 2021 Knowridge Science Report. All rights reserved.
