A newly designed 'brain alarm clock' can determine whether a person's brain ages faster than your Chronological age would assume 1 . This brains faster in women, in countries with more inequality and in Latin American countries, shows the alarm clock.

"The way your brain ages not only has to do with years. It depends on where you live, what you do, your socio -economic level, the level of contamination in your area," says Agustín Ibáñez, the main author of the study and neuroscientists at Adolfo Ibáñez University in Santiago. "Every country that wants to invest in the brain health of people must address structural inequalities."

The work is "really impressive," says neuroscientist Vladimir Hachinski from Western University in London, Canada, who was not involved in the study. It was published on August 26th in Nature Medicine

only connect

The researchers examined the aging of the brain by a complex form of Functional connectivity evaluated to what extent different brain regions interact with each other. The functional connectivity generally decreases with age.

The authors used data from 15 countries: 7 (Mexico, Cuba, Colombia, Peru, Brazil, Chile and Argentina) in Latin America or the Caribbean and 8 (China, Japan, the United States, Italy, Greece, Turkey, the United Kingdom and Ireland) who are not. Some of the 5,306 participants were healthy, some had Alzheimer's disease or another form of dementia and some had slight cognitive impairment, a forerunner of dementia.

The researchers measure the resting brain activity of the participants-if they do not do anything-either with Functional magnetic resonance tomography (FMRI) or electroencephalography (EEG). The first technique measures blood flow in the brain, and the second measures the activity of the brain waves.

The authors calculated the functional connectivity of the brain of each person and entered this data in two deep learning models trained on functional connectivity to predict the brain age, one for FMRI data and one for EEG data. They could then calculate the "brain gap" of each person - the difference between their chronological age and their estimated brain from functional connectivity. For example, a brain lead of ten years would mean that the brain connectivity is roughly that of someone who is ten years older than her.

unequal gaps

The models showed that people with Alzheimer or another kind of dementia had larger gaps in brain than those with Lightly cognitive impairment and healthy checks.

participants from Latin America or the Caribbean had an average of larger gaps in brain than those from other regions. Latin America is one of the most frequent regions in the world, says Ibáñez, and he thinks that this is why people from this region age faster. Structural socio-economic inequality, Strain from air pollution and Health differences were connected to larger brain gaps, especially for people from Latin America.

In addition, women who lived in countries with high gender equality -especially in Latin America and the Caribbean -tend to have greater gaps in brain than men in these countries.

other watches, other continents

to quantify the brain age in such a geographically various sample, is a phenomenal performance, says Hachinski. He believes that the conclusion that brain gaps vary is solid, but he warns that functional connectivity is only one way to measure the health of the brain, and that someone could have a lot of brain connectivity while, for example, due to diseases like Depression or anxiety suffers from poor intellectual health. The neuroscience is "not good at measuring design," he says.

A possible source for inconsistencies in the data is the variety of FMRI devices and EEGS -distributed over 15 nations -which the brain scans have delivered. For example, poorer countries could have had older devices, the data of lower quality produced than those from wealthier countries. However, Ibáñez found no connection between low data quality and larger brain gaps or higher structural inequality.

At the moment, Ibáñez 'team, whether brain gaps are related to the national income, compares brain gaps in groups from Asian countries and the United States and data from 'Epigenetic' watches that measure the biological age by examining chemical changes to DNA. Finally, Ibáñez hopes that the data will help develop personalized medical approaches that are based on the full biological diversity of the brains of people around the world.

"We have to understand this diversity," says Ibañez. "We cannot create really global science over dementia without tackling this."