Specific Biomarkers of Alzheimer's Disease Discovered

Studying the functional changes that occur in the brain during senile dementia of the Alzheimer type, researchers from the University of Madrid discovered biomarkers capable of predicting which patients with mild cognitive impairments are at increased risk of developing dementia, or senile dementia.

“In the course of the study, we found that two neural subsystems of the brain, which include the frontal-temporal and frontal-occipital areas, change as Alzheimer's disease progresses,” says Maria-Eugenia Lopez-Garcia, a researcher from the cognitive neurology group at the University of Madrid and one of the authors of the study.

In their work, the main findings of which were published in the scientific journal Brain, the scientists examined hypersynchronization (enhanced connectivity between different brain regions) as a key indicator of changes, and magnetoencephalography (MEG) as a tool for its detection. This allowed them to demonstrate that individuals with mild cognitive impairments who later develop Alzheimer's disease exhibit increased synchronization, but as dementia progresses, it weakens, indicating dysfunction of the cortical network.

Model X

Mild or moderate cognitive impairments are considered to be disturbances that go beyond age norms but do not yet limit a person's independence, meaning they do not significantly impact daily life and are almost imperceptible to others. It is believed to be an intermediate stage between normal age-related changes and dementia. On average, 15% of patients with mild cognitive impairment progress to Alzheimer's disease within a year.

Therefore, early detection of mild cognitive impairments, and especially the ability to classify patients who will develop them into dementia over time, according to Lopez-Garcia, “could help in identifying a dangerous condition, provide a prognosis, and make the assessment system for new drug or non-drug interventions available.”

For the three-year study, the researchers selected 54 patients with moderate cognitive impairments who were monitored every six months. They also used MEG results – a technology that allows measuring and visualizing the magnetic fields generated by the brain, taken at the beginning and end of the study.

The team then analyzed these results using methods used to assess brain synchronization: this allowed them to determine how different areas of the brain communicate with each other. At the end of the study, the condition of 28 patients remained unchanged, meaning they had the same degree of cognitive impairments, while the other half of the participants progressed to Alzheimer's disease. The model developed during the study showed success at nearly 97%.

“The synchronization data obtained at the preparatory and concluding stages of the study helped us create an explanatory model called Model X. It demonstrates that the presence of hypersynchronization predicts the transition from mild cognitive impairment to dementia, showing a decrease in its level as the disease progresses,” the researchers explained.

According to the World Health Organization, nearly 36 million people worldwide currently live with a diagnosis of dementia. This term refers to a severe progressive neurodegenerative disease associated with aging, characterized by pronounced and persistent impairment of intellectual activity and emotional-volitional sphere, ultimately leading to complete personality disintegration.

It is one of the leading causes of disability and dependence among the elderly worldwide. In the United States alone, dementia claims more lives each year than breast and prostate cancers combined. It is projected that the number of people affected by this ailment will double by 2030, and triple in another twenty years. The overwhelming majority will suffer from Alzheimer's disease.

“The emergence of a non-invasive biomarker for early development could help people recognize this severe irreversible disease in a timely manner. As researchers, we aim to be helpful and to make discoveries that can deepen our understanding of this complex ailment,” concludes Lopez-Garcia.