Brain Age is not a medical indicator, but rather a type of index, and acts as a good indicator to use to understand the state of your brain, and to check the effect of cognitive training.
It is calculated by comparing the results of tests such as memory and calculation skills with the results of people of various ages who have taken the same tests.
In general, typical cognitive functions such as mental math and short-term memory peak when we are in our twenties, and decline linearly with age. By obtaining the correlation between the actual age and a cognitive task score in advance, it is possible to calculate a “brain age” by taking a cognitive test.
For example, if someone's Brain Age is 50 years old, that means their performance in the test is close to those people in the 50 years old age group among all those that have taken the same test.