a Nature Medicine According to recent international research published in the journal, a distinction can be made between four basic types of Alzheimer’s disease, which lead to different symptoms and a different course.
Alzheimer’s disease, described by Alois Alzheimer’s in 1906, is a disease involving brain damage and mental degeneration, the cause or treatment of which is currently unknown. The disease usually occurs with age, but it can occur much earlier in a tenth of cases, even among those in their 30s. In 2020, 50 million cases of dementia are known worldwide, two-thirds of which are caused by Alzheimer’s disease.
To the best of our knowledge, the causes of the disease are high levels of beta-amyloid and tau proteins in the Alzheimer’s disease brain. Recent results indicate that the latter is responsible for brain cell death. The disease has been described in one model in recent decades, and the recurrent symptoms that emerge from it have been recorded as individual characteristics.
Contrary to our interpretation thus far, our results show that at least four patterns can be distinguished in cerebral tau pathology. Consequently, Alzheimer’s is more of a disease than previously thought. We need to reinterpret Alzheimer’s disease paradigms and the methods used to staging the disease
Said research author Jacob Vogel of McGill University.
The algorithm was unbiased
The study, involving experts from Sweden, Canada, the United States and Korea, examined the largest and most diverse group of patients studied so far using positron emission tomography (PET), which detects tau proteins. Of the 1,612 people, 1,143 developed long-term symptoms of Alzheimer’s disease. The recordings were scanned with a so-called SuStaIn algorithm – the automated process showed the subtypes neutrally.
Four distinct pathological patterns of tau emerged over time. These subgroups represent between 18 and 30 percent, which means that they are all common and there is no major variant of Alzheimer’s disease, as we thought.
Said Oscar Hanson who participated in the research.
- Option 1: tauk mainly attacks the temporal lobe and affects memory more strongly. It is typical in 33 percent of cases.
- The second alternative is that it attacks the cerebral cortex, causing milder disturbances in memory, and even problems in planning and executing actions. It accounts for 18 percent of cases.
- The third alternative: proteins attack the visual cortex, causing disturbances in the recognition of different shapes and orientations. It causes 30 percent of cases.
- Fourth option: the tauk appears asymmetrically in the left hemisphere and destroys language skills. 19 percent of cases are like this.
Oscar Hanson explained that a large database of tau-PET recordings and the application of machine learning led to the discovery. A five to ten year research program will be launched to gain a deeper understanding of the characteristics of the subspecies with the hope that the new knowledge will lead to more effective personalized treatments.