I Study Cognition & This Is How To Know How "Old" Your Brain Is

While there's no test you can take at home to definitively say how "old" or "young" your brain is, we can think of a young and healthy brain as being at peak function. And, most often, peak brain function is associated with a sharp memory. As we get older, it can be difficult to remember names, faces, events, something we just read, or what we ate. 

In younger brains, the process called neural differentiation is efficient and robust. In this process, specific brain cells are tasked to remember certain types of information, such as faces. As we age, that process deteriorates, so the cells lose their specificity and do not function as well. Instead of just focusing on faces, they try to remember other types of information as well. For a SuperAger, neural differentiation is akin to that of a twenty-five-year-old. That's part of the reason why a SuperAger has the memory performance of a twenty-five-year-old.

So what else are the secrets of these SuperAgers with robust memory—and all those with brain ages younger than their chronological age? A study published in 2021 uncovered some surprising answers. Over eighteen months, the study followed 330 people, referred to as SuperAgers, who were 100 years or older; the researchers found no decline in most areas of memory or cognitive abilities2. 

While a year and a half might not sound like a long time, once a person reaches the century mark, two years for them is like twenty-five years for a seventy-five-year-old in terms of brain health. For example, the risk for developing dementia3 increases by 60 percent every two years after the age of 100, while it takes twenty-five years for a 75-year-old's risk of dementia to increase by the same amount. In other words, twenty-five years of risk is compressed into two years after the age of 100.

So, what is the secret of these mentally strong centenarians? You might be tempted to guess "genes." While genes can definitely play a role, 16.8 percent of the people in the study had genes that are known to raise the risk of Alzheimer's, and they did not develop the disease. What seemed to be a key piece of the puzzle was lifestyle!

One key factor was that they kept learning new things throughout their life. Remember, your memories are housed in those connections between your brain cells. Think of your brain like a bank account; the more deposits we make, the less our net worth is affected by withdrawals. We make deposits (new connections) by learning new things; as we age and naturally lose some of those connections, there are simply more remaining. There's a Spanish saying: "Learn one new thing each day." This simple advice is an excellent first rule for brain health—learning new information or a new skill keeps your brain young. So, if you are learning something new by reading this right now, you are doing one of the most important things for your brain.

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While we are not at the point where every person can slide into a brain scanner and find out their brain age, here are just a couple of factors that can help give you a sense of your brain age. Ask yourself the following five questions. 

To remember these five questions, I created the mnemonic B.R.A.I.N., where the first letter of each question corresponds to a letter in the word “brain.” 

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Use this B.R.A.I.N. mnemonic to quiz yourself tomorrow on these five questions. Mnemonics are an excellent way to remember information. Since recall is a use-or-lose-it skill and one of the five questions, here's a fun chance to practice.  

Of course, none of these questions can replace an actual brain scan and comprehensive evaluation by a neurologist. Still, these fundamental categories can help us get a sense of brain age. It is important to note that simply determining someone's brain age by brain scan is also not without complexity and controversy9.

For example, there is the issue of which part of the brain and which biomarkers, such as white or gray matter, iron deposits, and volume, to investigate or prioritize. Be wary of a private clinic offering to tell you your brain age, especially for a hefty fee, as at this point this tool is primarily being used accurately at large research institutions. For that matter, be wary if it's an offer from a guy in a van for a bargain fee. 

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