Everybody knows that our bodies start changing as we age. We develop grey hair, while our skin shows signs of aging in the form of wrinkles. We also feel the stiffness in our joints and muscles. These are some of the physically visible and apparent changes of aging that we see on a day-to-day basis. However, there are some subtle changes that happen in our brains as well due to aging. Factors like the sharpness of our thinking and the ability to communicate, as well as our memory all, start to change subtly over the years. If you want to learn more about the way aging affects the brain, read on to understand how the brain changes with age in cognitive decline.
Stages of Cognitive Decline as we Age
Just like how our joints and muscles begin to stiffen as we age, there is evidence that certain cells in our brain also start stiffening up.(1) As we get older, a lot of people may start to notice changes in many other, not-so-obvious things as well, including your thinking skills. For many people, cognitive decline occurs with age. Cognitive decline is a term used to refer to the gradual loss of thinking abilities that includes the ability to remember, learn, reasoning, and pay attention.(2, 3, 4)
While some people experience some amount of cognitive decline with age, but there are many other significant changes that can also be an indication of a cognitive disorder.(5)
Illness, injury, and poor health habits can have an influence on how much cognitive decline you experience, as well as how rapidly your cognitive abilities begin to decline. Medical experts typically recognize four stages of cognitive decline as people age. These include:
- Stage 1 No Cognitive Impairment (NCI): At stage one, you don’t tend to experience any change or difference in your thinking skills or in any of the complex abilities that make up cognition.(6, 7)
- Stage 2 Subjective Cognitive Decline (SCD): It is in stage two that you begin to notice that certain thinking abilities start to decline, but the decline is not enough that it starts to interfere with how you function on a daily basis.(8, 9)
- Stage 3 Mild Cognitive Impairment (MCI): In stage three of cognitive decline, you start experiencing a decline in the ability to remember, reason, make judgments, perceive the world around you, and even use language properly.(10, 11)
- Stage 4 Dementia: Dementia is the last stage of cognitive decline, where you begin to have trouble doing day-to-day activities and chores. You will find having trouble with activities like paying bills, driving, taking care of your home, and even in taking care of your health.(12)
While stages one and two are more common in people as they get older, mild cognitive impairment and dementia are classified as cognitive disorders having symptoms that vary in severity.
What Cognitive Changes Occur in the Brain As You Age?
The natural process of aging brings along with it several subtle changes in one’s cognitive abilities. You may begin to notice that remembering new information and recalling numbers and names take just a bit longer. At the same time, autobiographical memory of the major events in your life, along with the accumulated knowledge you have, both start to decline as you get older. Both of these are types of declarative memory. On the other hand, procedural memories, such as knowing how to tie a shoe, driving a car, or riding a bike, are typically unaffected and remain more or less the same as you age.(13)
Another type of memory that also declines naturally with age is your working memory, which is the ability of the brain to remember a piece of information, such as a password, phone number, etc. Some studies have shown that your working memory can actually begin to decline as early as in your 30s.(14) Processing speed and problem-solving skills are also related to this type of memory, and these also start to decline as you age.
Another aspect of the brain that gets affected by aging is your attention span. You may find that you have a challenging time focusing on what others around you are saying when you are in a noisy environment. The ability to separate out or tune out distractions while concentrating on a particular thing also gets affected. As you get older, splitting your focus between two tasks also becomes more challenging.
Structural Changes in the Brain As You Age
Not all changes are limited to your cognitive function. These changes in your cognitive ability are a reflection of the changes that are happening to the brain’s chemistry and structure. As you enter your middle ages, your brain changes in ways that are subtle but very much measurable. For example, the actual volume of the brain starts to shrink when you enter your 30s or 40s. This rate of shrinkage further increases as your each 60.(15)
However, this loss of volume is often not the same throughout the brain. Some parts of the brain tend to shrink faster and more than others. The cerebellum, prefrontal cortex, and hippocampus are known to experience the biggest volume losses, and this continues to worsen as you age further.(16, 17)
In fact, the cerebral cortex, which is the wrinkly outer layer of the brain that is home to all the neuron cell bodies, also starts to thin out as we get older. This cortical thinning actually follows a pattern that is similar to the volume loss of other parts of the brain, and it is especially apparent in some parts of the temporal lobes and the frontal lobes.(18)
It is interesting to note that the parts of the brain that experience the maximum structural changes as you get older are also the same parts that are among the last ones to mature in adolescence. This has caused experts to propose a theory of brain aging that hinges on ‘last in, first out,’ meaning that the last parts of the brain that developed were also the first ones to start deteriorating. And studies carried out on changes to the brain’s white matter owing to natural aging further supports this hypothesis.(19, 20, 21)
What are the Signs of Cognitive Decline of the Brain?
The signs of cognitive decline vary from person to person because everyone is different when it comes to their health profile, life circumstances, level of physical activity, diet, and other such factors. Nevertheless, there are some patterns that remain more or less the same when it comes to experiencing cognitive decline.
People with mild cognitive decline may:
- Lose or misplace things
- Have trouble finding the correct words to express themselves
- Forget their passwords, appointments, or scheduled events
- Get anxious or overwhelmed about doing complex tasks or projects
It is essential to realize that forgetting things every now and then is not the same as cognitive decline, and neither does regular forgetfulness indicate a sign of cognitive decline.
At What Age Does Cognitive Decline Begin?
Again, as mentioned above, cognitive decline progresses at a different rate in different people. Your healthy lifestyle has a big role to play and has a lot of influence on what age your brain functions begin to decline.
An analysis carried out by the Health and Retirement Study in 2020, which had over 29,000 participants, discovered that women usually start to experience signs of cognitive impairment around the age of 73, while men begin to experience the same near the age of 70, experiencing dementia by the age of 79 years. Those women, meanwhile, who further go on to develop dementia do so at around 83 years old.(22) However, not everyone who has cognitive decline will go on to develop dementia. The study also found that education level and race had an effect on the age of onset.
People with higher education levels usually tend to experience the signs of cognitive decline at a later age. This is believed to be because they remain active mentally and interact more socially till a later stage in their life. They are also more likely to have better access to healthcare and the option of treating medical problems at an early stage itself.(22)
Risk Factors to Faster Cognitive Decline
Family history and genetics are the major risk factors for cognitive decline. Other factors can also cause you to experience signs of cognitive decline at an earlier age. These include:
Some of these factors you cannot do anything about, but some are within your control, such as quitting smoking at the earliest. Certain age-related cognitive changes are also related to your genetics, and there is not much that you can do to change this risk factor. Nevertheless, there are many things you can do to keep your brain healthy, active and preserve the ability to think for a longer age.
Some steps you can take to keep your brain active and healthy include:(23)
- Eat a nutritious and well-balanced diet that includes lots of leafy green vegetables, fresh fruits, and whole grains.
- Exercise regularly.
- Limit your intake of alcohol.
- If you smoke, seek help to quit.
- Avoid using other tobacco products.
- Protect yourself from getting a brain injury.
- Remain socially active.
- Stimulate your brain by engaging in activities, reading, having hobbies, playing games, etc.
As you start to get older, you are likely to notice changes in your ability to communicate, reason, and remember. For many people, such cognitive changes are a normal part of aging, while for others, they may be more pronounced and severe enough to disrupt their daily lives. If you feel that these symptoms of cognitive decline are having an impact on your life, you should seek medical assistance and consult a doctor to find out whether you are at risk for developing more severe brain changes. Following a healthy lifestyle and diet, experiencing regularly, and staying active both physically and mentally can help keep your brain healthy as you get older.
- staff, S.X. (2019) Scientists reverse aging process in rat brain stem cells, Medical Xpress – medical research advances and health news. Medical Xpress. Available at: https://medicalxpress.com/news/2019-08-scientists-reverse-aging-rat-brain.html (Accessed: October 22, 2022).
- How the aging brain affects thinking (no date) National Institute on Aging. U.S. Department of Health and Human Services. Available at: https://www.nia.nih.gov/health/how-aging-brain-affects-thinking (Accessed: October 22, 2022).
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- Matthews, F.E., Stephan, B.C., McKeith, I.G., Bond, J., Brayne, C. and Medical Research Council Cognitive Function and Ageing Study, 2008. Two‐year progression from mild cognitive impairment to dementia: to what extent do different definitions agree?. Journal of the American Geriatrics Society, 56(8), pp.1424-1433.
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- De Beni, R. and Palladino, P., 2004. Decline in working memory updating through ageing: Intrusion error analyses. Memory, 12(1), pp.75-89.
- Rodrigue, K.M. and Kennedy, K.M., 2011. The cognitive consequences of structural changes to the aging brain. Handbook of the Psychology of Aging, pp.73-91.
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