The 11 types of Alzheimer's (and how to differentiate them)

Official data indicates that almost 50 million people in the world suffer from some form of dementia. Each year, 8 million new cases of these diseases that severely affect memory, thinking, understanding, coordination and social skills are diagnosed, especially after 65 years of age.

And of these, up to 70% correspond to Alzheimer's, one of nature's cruelest disorders. A neurological disease with no cure and whose causes are unknown that causes severe memory impairment and, ultimately, when the brain can no longer maintain stable vital functions, death.

It is a horrible disease and, despite being the most common form of dementia in the world, it is still largely unknown to science. But little by little, we are advancing in their knowledge. And one of the most important steps was achieved in April 2021, with a study that showed that, at a clinical level, the progress of this pathology can be of 4 different types.

Thus, in today's article, hand in hand with both this article and other prestigious scientific publications that you can consult in the final section of references, in addition to understanding the bases of Alzheimer's, we will explore the particularities of the different subtypes of this neurological disorder. Let us begin.

What is Alzheimer's?

Alzheimer's is the most common cause of dementia and consists of a neurological disorder in which there is a progressive deterioration of brain cells. With this disease, brain neurons gradually degenerate until they die. If there are 50 million cases of dementia in the world, it is estimated that between 50% and 70% could be Alzheimer's.

The pathology causes a slow but continuous loss of mental capacity, something that inevitably results in a loss of social, physical and behavioral skills. Cases appear after 65 years of age and, over time, the person is unable to live independently.

After several years of disease involvement, Alzheimer's causes severe memory impairment (first, the short-term and, finally, the long-term), reasoning, sociability, physical skills, speech, understanding, control of emotions, behavior and, Ultimately, when the neurological damage is such that stable functions cannot even be maintained, it causes the death of the person.

And, unfortunately, the causes are not known. We know that there are different risk factors (which even includes poor dental hygiene), but their exact origin remains a mystery. Something that prevents us from effectively preventing Alzheimer's and that, as with other neurological pathologies, there is a cure.

And it is that although there are medications that temporarily improve symptoms so that the patient can maintain their autonomy and independence for as long as possible, with no cure, there is no way to prevent the disease from progressing to the fateful outcome. Therefore, any progress that is made in the knowledge of this disorder is taken as a great success in the field. And now we are going to analyze one of the most important.

What kinds of Alzheimer's disease are there?

In April 2021, a scientific article was published that marked a real revolution in the field of neurology. Four distinct trajectories of tau deposition identified in Alzheimer's disease showed us how Alzheimer's can be classified into different subtypes according to its progress and symptoms, something that, according to the authors, should make us stop thinking about a “typical Alzheimer's” and begin to clinically approach the different entities individually.

But in addition to these four subtypes, we can also classify Alzheimer's according to its severity, its appearance and its associated inflammatory reactions. Thus, these are the main types of Alzheimer's that exist and that can be differentiated clinically.

1. Limbic Alzheimer's

Limbic Alzheimer's, known as subtype 1, is the variant observed in 33% of patients with this form of dementia and is what we can consider as “typical Alzheimer's”. It has a late onset and, although patients with this variety show better results in terms of cognitive abilities, memory loss is more severe.

2. Temporary mild Alzheimer's

Temporary middle Alzheimer's, also known as subtype 2 or MTL, is the variant observed in 18% of cases and is the one with the earliest appearance, with a special affectation to the executive functions. At the same time, it is, as far as possible, the one that least affects memory.

3. Later Alzheimer's

Later Alzheimer's, also known as subtype 3, is the variant observed in 30% of cases. The affectation occurs especially in the visual cortexIt is slower in progress and the onset is also late. It stands out, at a clinical level, for the damaging effects on visual-spatial skills.

4. Temporary lateral Alzheimer's

Temporal lateral Alzheimer's disease, also known as subtype 4, is the variant observed in 19% of cases and is characterized especially by its asymmetry, since the left hemisphere of the brain is the most affected. Its progress is faster, it stands out for the damage in the ability of the language and its appearance is particularly early. With this variant, we end up with the subtypes described by the aforementioned article. But there is more.

5. Mild Alzheimer's

According to the severity of the pathology, Alzheimer's can be classified into three groups: mild, moderate and severe. It should be noted, however, that a patient with this disease will go through all three classes, since the slow but continuous progress means that, although it begins with the mild phase, it ends up entering the most severe.

Be that as it may, by mild Alzheimer's we understand that stage of the pathology in which the symptoms are less intense and, sometimes, even difficult to perceive. These are the first manifestations of cognitive impairmentTherefore, although there may be problems remembering daily tasks, the patient maintains his autonomy and severe clinical signs are not observed.

6. Moderate Alzheimer's

Over time, Alzheimer's, which started out mild, moves to the next phase. By moderate Alzheimer's we understand that stage of the pathology in which symptoms become more intense. Memory loss becomes noticeable, problems arise in the control of emotions and sociability, confusion becomes more noticeable and, although physical capacities have not yet been damaged, it is difficult for them to maintain their full autonomy.

7. Severe Alzheimer's

Alzheimer's is a disease without cure and of unstoppable progress, so inevitably, the patient will end up entering the last and most severe phase of the disease. By severe Alzheimer's we understand the final stage of the pathology, with the most severe symptoms and with a profound effect on memory, physical capacities and social skills.

The patient does not communicate, he has lost his memory in the short, medium and long term, his physical capacities are greatly diminishing and he has already lost his autonomy. Over time, when the brain is no longer able to even maintain stable vital functions due to neurological damage, death will inevitably come.

8. Inflammatory Alzheimer's

Inflammatory Alzheimer's is that variant of the disease in which, in addition to the cognitive and physical symptoms that we have already mentioned, a high amount of C-reactive protein is observed, a protein produced by the liver and sent into the bloodstream in response to inflammation. This can cause pain, redness, and swelling in different regions of the body.

9. Non-inflammatory Alzheimer's

Alzheimer's, although the variant that we have just described exists, is not considered an inflammatory disease. And it is that many times, it is not linked to high levels of inflammatory biomarkers such as this C-reactive protein. Thus, a case of non-inflammatory Alzheimer's is one that it is not associated with inflammation reactions, but it can be linked to other metabolic abnormalities. For example, the subtype Cortical is due to deficiencies of zinc (an important mineral for cell division) in different areas of the brain.

10. Late-onset Alzheimer's

Finally, we can classify Alzheimer's into two varieties according to its moment of appearance. Late-onset Alzheimer's is one that appears after the age of 65. It is the most common form of the disease, since, in fact, 95% of Alzheimer's cases appear (or, at least, show the first symptoms) after the age of 65.

11. Early-onset Alzheimer's

Finally, early-onset Alzheimer's, also known as precocious Alzheimer's, which is the strangest variety, is that which appears before the age of 65. Only 5% of Alzheimer's cases are diagnosed before this age. Generally, these cases of early Alzheimer's (which appear between the ages of 40 and 50) are due to strange genetic factors and with certain heritability.