How to avoid age-related cognitive deterioration  

After a certain age, absent-mindedness, difficulty finding a particular word, and forgetfulness go from being anecdotal to something that could raise alarm bells for those who experience them, and their loved ones. “Senior moment,” people say with a nervous laugh, worried that such slips could be early signs of cognitive decline capable of leading to dementia, a path that is often assumed to be inevitable. But is it? Surely, the elderly who are often called — even if it comes with some accompanying level of surprise — “sharp as a tack” are proof that this is not always the case?

The World Alzheimer Report 2024, from Alzheimer’s Disease International, makes it clear that considering dementia a foregone conclusion is a widespread practice: 80% of the population (and 65% of health professionals) “incorrectly” believe that dementia is a normal part of aging. “It’s yet another stereotype associated with aging,” says Gregorio Jiménez Día, a geriatrics specialist and deputy secretary of the Spanish Society of Geriatrics and Gerontology. All the experts consulted for this article agree that cognitive changes do occur with age, but that not all represent deterioration and, of course, not all inevitably lead to dementia.

“Cognitive deterioration is frequent, but it’s not unavoidable. And it’s important to distinguish between age-related cognitive changes and those that lead to some kind of illness,” says Raquel Sánchez del Valle, coordinator of the Behavior and Dementia Studies group at the Spanish Society of Neurology. Although those illnesses are more frequent among older people (“nearly a third of people aged over 85 have some kind of illness that leads to cognitive deterioration,” says the expert), it’s not entirely correct that this kind of deterioration is caused by aging. The neurologist uses walking as an example. We tend to walk slower when we are 85 than we do at 20, but that loss of speed isn’t a pathological process. Not being able to walk — or having cognitive decline or dementia — is pathological and not caused by age, although it may be more common among older people.

Not all changes are for the worse

The Spanish Royal National Academy of Medicine (RANM)’s dictionary of medical terms defines cognition as the “set of mental activities (thinking, perception, will, memorization, memory, learning) that enable human beings to acquire knowledge and use it in all their actions.” In other words, there are many cognitive processes and although they all change over time, they do not all change identically. “The brain does not function in a uniform way,” confirms Sánchez del Valle.

Let’s start with those that are perceived as a deterioration. During a normal aging process, one of the cognitive changes that is caused is that of processing speed: we process information more slowly (similar to how we walk more slowly). Our capacity to multitask is also affected. “When we are young, we are able to stay focused on many tasks; doing several things in parallel is no problem for us. One of the things that happens as we become older is that we start losing that capacity,” says Javier Sáez Valero, head of the altered molecular mechanisms in Alzheimer’s disease and other dementias group at the Institute of Neurosciences, a joint project of Spain’s National Research Council (CSIC) and Miguel Hernández University. The expert emphasizes that he is talking about becoming older, not aging, because difficulties in multitasking can happen “beginning in one’s twenties.” The same applies to the slowdown in processing speed: that starts around the age of 30.

Why does that happen? “Possibly, it’s related to the fact that there is a moment in which, although we are still establishing new neuronal networks on which memory and learning are based, molecular mechanisms that serve to sustain all of this begin to fail. This manifests in a loss of capacity, especially in short-term memory. But pathological aging is not the same as normal, physiological aging,” says Sáez Valero, in agreement with Sánchez del Valle.

Although we tend to focus more on what goes wrong than on what improves as we age, that does not mean that there is no positive side. As the brain is not uniform, there are cognitive processes that improve with age, “some even without limit,” says Sánchez del Valle. One of these is semantic memory, which the RANM dictionary defines as memory that “stores an event evoked in the form of memories that can be expressed in words” and which is “the basis of knowledge of the world and its rules, of the meanings of words, of their functions and qualities.” Emotional processing and responses to other people’s emotions may also improve.

Believing that all changes are for the worse also has emotional consequences. “When seniors perceive their thought process as becoming slower, that they need more time to make decisions or that it takes more time to get their bearings, or the fact that those around them act in an overprotective manner, treating them like children, or excluding them from decision-making, it can be very painful for them,” says Jiménez Día.

How to age with a healthy brain

In the puzzle of how the passage of time changes the brain, one piece that still doesn’t fit is that of the “superagers,” people who grow older without any deterioration in their cognitive performance. Like those who run marathons at 80, they are a minority, but they exist, and they may hold one of the secrets to preventing cognitive decline and dementia.

However, the information we have on superagers is still inconclusive. In recent years, organizations in Spain, led by the Queen Sofía Alzheimer’s Foundation in Madrid, have published a couple of studies investigating super-elderly people whose episodic memory has remained similar to that of people 30 years younger. They found that their brains showed less atrophy, more volume in key memory regions, and better connectivity between areas that are important to cognition.

Another interesting aspect is that, although they had less atrophy, they did have a similar volume of lesions compared to the control group. Studies link this to the concepts of resistance and resilience, which Sánchez del Valle also mentions. “It’s one thing for your brain to be able to cope with disease, for you not to develop disease in your brain, that’s resistance. It’s another thing for your brain to remain efficient even though you have disease [the lesions]. That would be resilience,” she says. “In the end, it’s a combination of both factors.” These superagers also walked faster and had better cardiovascular markers, but it is not clear what that association means. That better physical health could be both the cause and the consequence of a brain in better condition is one option.

The fact that there is no foolproof recipe for super-aging (or, less ambitiously, simply for experiencing the cognitive changes associated with age without developing something pathological) does not mean that there are not a few basic recommendations for giving our brains a better chance of coping with the passing years.

“Beyond the genetic factors that explain a percentage of cases of degenerative dementia, a good number of the risk factors for developing dementia could be preventable or controllable throughout our lives, starting at a very early age,” says Jiménez Díaz. “In the early years, achieving a higher level of education would be a protective factor. In later life, it would be important to avoid alcohol consumption and protect ourselves from head injuries, as well as ensuring good blood pressure control and avoiding obesity. Later on, we should continue to maintain good physical activity, stay away from toxins such as tobacco, avoid isolation by maintaining a good social network around us, and diagnose or control chronic diseases such as diabetes in a timely manner, as well as achieve good sleep hygiene and detect the onset of depressive symptoms early on. Along with this, there are factors that are more difficult to change from a personal perspective, such as air pollution in large cities,” says the expert.

These are some of the 14 risk factors for identifying dementia identified in a study published in The Lancet in the summer of 2024. According to that study, avoiding these factors could prevent almost half of all cases of dementia. Even so, we are talking about probabilities. “There are people who do everything right and still develop dementia and vice-versa,” says Sánchez del Valle.

When to worry

Where is the border between normal cognitive deterioration and dementia? We begin to talk about cognitive deterioration when there is a cognitive loss greater than that which is expected for one’s age and educational level, says Sánchez del Valle. “When this cognitive deterioration affects a person’s functionality, that is to say, when there are things that they have to stop doing because these cognitive changes are on a magnitude that prevents them from carrying out a certain function, we’re talking about dementia,” she says. In other words, if someone with memory problems can simply make a list and continue going to the supermarket with no issue, that is cognitive deterioration. But if it affects a person’s functionality, if they can no longer go grocery shopping on their own due to cognitive issues, that’s dementia. As stated in an article published in the Spanish Journal of Geriatrics and Gerontology, when the term “mild cognitive impairment” was coined in 1988, it was believed to always be a degenerative process that preceded dementia. However, “in the last 30 years,” it has been found that not all patients follow this path.

To be able to detect when something is happening beyond the normal effects of aging, Sánchez del Valle points to several factors. “Your performance is worse than that of the people around you, and in addition, those changes are persistent and progressive. That is to say, it’s not that you’re forgetting something once every three months, but that it’s something that happens frequently throughout the day and it gets worse over time,” she explains.

Sáez Valero also talks about memory gaps that are merely attention issues. “If after you leave the house, you go back to check to see if you’ve left the lights on, that problem is simply due to the fact that you weren’t paying attention at that moment,” he says. “With the loss of cognitive skills, especially amnesia, we lose our sense of context. Someone suddenly finds themselves on the street and doesn’t know where they are.” In these cases — and if you have any suspicions related to them — it’s best to seek medical advice for a professional assessment.

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