Alzheimer's "is not a disease" and can be grouped into six distinct categories, the researchers said.
The scientists examined five existing medical studies that analyzed more than 4,000 patients who fought the memory disorder.
They found that Alzheimer's could be divided into six different groups, depending on how bad the patients were affected. And all had genetic differences.
The 18-person research team, coming from a number of prestigious universities, hopes the results will bring them one step closer to treating Alzheimer's.
And they also argue that the results could explain why studies that treat all patients with the same drugs often turn out to be unsuccessful.
The scientists revealed that Alzheimer's "is not a disease" and can be grouped into six distinct categories. They hope this will take us one step closer to a cure (stock)
Attempts to stop the neurological disease have failed until scientists have been sure of the exact cause.
Alzheimer's disease – the most common form of dementia – affects about 5.5 million people in the United States and 500,000 in the United Kingdom, as figures show.
The study involved researchers from Boston University, the Virginia Puget Sound Health Care System and the Indiana University.
The project was led by dr. Shubhabrata Mukherjee, from the Department of General Practice at the University of Washington, Seattle.
"Alzheimer's, like breast cancer, is not a disease," said Dr. Mukherjee on the back of the results.
"I think a good drug could fail in a clinical trial because not all subjects have the same type of Alzheimer's."
"This study is not the end, it's a start", added Dr. Results Mukherjee, published in the journal Molecular Psychiatry.
All participants had late-onset Alzheimer's, the most common form of the disease, when someone is diagnosed at age 65 or older.
After more than two years of attempts, the researchers have succeeded in standardizing the scores of the cognitive tests of the different studies.
All evaluated patients on four key factors: memory, language, "executive functioning" and "visuospatial functioning".
Executive functioning is the set of skills that allows a person to do things, such as time management and attention to activities.
Visuospatial functioning refers to the way a person relates visual information to the surrounding space. This is used when walking through a door to avoid bumping into the frame and when crossing the road to measure the speed of an incoming car.
WHAT ARE THE SIX DIFFERENT TYPES OF ALZHEIMER?
After examining five studies with a total of 4,050 patients with Alzheimer's, US researchers revealed that people with the disease can be divided into the following six categories:
- Those who obtain equal scores on memory, language, executive functioning (skills that allow you to obtain results, such as time management) and visuospatial functioning (how a person relates visual information with the space around them, for example when you walk)
- Those who get the worst score in the memory tests
- Those who get worse results in language tests
- Those who get the worst score in visuospatial functioning tests
- Those who get the worst score in the executive run tests
- Those who get the worst score in two of the four tests
The researchers then used data to group patients into six different types of Alzheimer's.
The dott. Mukherjee and colleagues found that 39% of patients achieved average scores on all four factors.
The second largest group, in which 27% participated, included those whose memory scores were substantially worse than the other results.
In smaller groups, 13% of participants had significantly lower language scores than others, while 12% had a worse score in visuospatial functioning.
Only three percent of participants achieved substantially worse results in executive functioning tests than the other three factors.
6% of patients were bracketed in the final group, which saw them worsen on two of the four factors.
The researchers then analyzed the DNA of 2,431 participants to determine if genetic subgroups exist between different types of Alzheimer's.
They found 33 specific positions across the genetic makeup of patients influencing the Alzheimer's group they belong to.
A variant of the APOE gene, which is strongly associated with Alzheimer's in Europeans, has proved to be particularly linked to those with poor memories.
Although tests can identify whether a person is a carrier of the APOE gene, the researchers point out that not all those with the gene develop Alzheimer's and some even get sick without it.
Several years ago, the Genomics International of Alzheimer & # 39; s Project Consortium published the largest genetic study on Alzheimer's.
They found about 20 DNA locations associated with the disease and classified it as one disease.
The researchers hope their study contributes to a cure, which world leaders hope to achieve by 2025, but effective treatment has not yet been developed.
The co-author of the study, dr. Paul Crane, of Washington University, said: "We have found substantial biological differences between cognitively defined subgroups of patients with Alzheimer's, the implications are exciting."
Attempts to stop the memory disorder in its tracks have so far focused on the toxic development of beta-amyloid protein in the brains of patients. This gradually destroys the neurons, causing memory loss and confusion.
However, last September, researchers at King & # 39; s College said that once these groups were formed it is "too late for drugs" to work.
WHAT IS ALZHEIMER & # 39; S?
Alzheimer's disease is a progressive and degenerative disease of the brain, in which the accumulation of abnormal proteins causes the death of nerve cells.
This upsets the transmitters that carry messages and causes the brain to shrink.
More than 5 million suffer from the disease in the United States, where it is the sixth cause of death.
When brain cells die, the functions they provide are lost.
This includes memory, orientation and ability to think and reason.
The progression of the disease is slow and gradual.
On average, patients live five to seven years after diagnosis, but some can live for ten to 15 years.
- Short-term memory loss
- Behavioral changes
- Mood swings
- Difficulty managing money or making a phone call
- Serious loss of memory, forgetting close family members, objects or familiar places
- Becoming anxious and frustrated by the inability to make sense of the world, leading to aggressive behavior
- Eventually lose the ability to walk
- He may have trouble eating
- Most will eventually need assistance 24 hours a day
Source: Alzheimer's Association