Is it inevitable you’re going to get dementia?

Is the memory loss and mental decline of dementia an inevitable part of getting older Let’s look at what healthy ageing looks like and compare it to the mental decline and memory loss caused by dementia.

Many of us get more forgetful as we get older. Most people need a bit longer to remember things, get distracted more easily or struggle to do some tasks as well as they used to. This may become more noticeable when we reach middle age, during our 40s, 50 and 60s.  These changes are completely normal, but can be frustrating and many people worry that they’re the early sign of dementia.

In fact, many people think of dementia as an inevitable part getting older. In this episode, I want to show you that, although it is certainly true to say that the symptoms of dementia are most common in older people, dementia is not a normal part of ageing. It’s not inevitable that as you get older, you’ll end up with dementia. You can live for 100 years without any of the signs or symptoms of dementia. Neither is the mental decline in dementia just an exaggeration of getting old. Dementia is caused by brain diseases and it is not part of the normal process of healthy ageing.

So I want to explain the difference between healthy ageing, the mild mental decline, called mild cognitive impairment, that often precedes Alzheimer and other forms of dementia and the dementia itself.  Let’s start with what healthy ageing looks like.

Healthy Ageing

Healthy ageing does bring subtle changes to our mental abilities and brain function. The changes in our ability to think and remember as we get older are a normal part of the ageing process. Some mental abilities become worse with age, while some others may actually improve, but it’s important to keep in mind that there’s enormous variability across individuals.

Committing new information to memory and recalling names and numbers can take a little longer as we get older. Our autobiographical memory of life events and accumulated knowledge of learned facts and information, what we call declarative memory, both decline with age, whereas procedural memories like remembering how to ride a bike, play the piano or tie a shoe lace remain largely unaffected as we get older.

The ability to hold a piece of information in mind, such as a phone number, password, or where the car is parked — what we call working memory - also declines with age. Some studies suggest a slow decline the starts as early as our thirties.

Certain aspects of attention can also become more difficult as our brains age. We may have a harder time focusing on what our friends are saying when we’re in a noisy restaurant. And splitting our focus between two tasks – like holding a conversation while driving – also becomes more challenging with age.

But not all of our mental abilities decline with age. Some actually improve. For example, you often have better verbal, reasoning and mathematical abilities, in middle age than you did when you were younger. And reading ability and vocabulary also remain unchanged or even improve as we get older. So contrary to the adage that you can’t teach an old dog new tricks, there is growing evidence that we can and do keep learning throughout our lives.

All of these alterations in mental ability reflect changes in the brain’s structure and function. As we enter midlife, our brains change in subtle ways. The overall size of the brain begins to shrink when we’re in our 30s or 40s, with the rate of shrinkage increasing around age 60. Some brain areas shrink more, and faster, than other areas. The parts of the brain associated with memory, thinking, reasoning and planning, at the front, and balance and coordination, at the back, show the biggest shrinkage, which worsen as we get older.

The insulation around brain cells starts to erode, slowing down messaging between different parts of the brain, and arteries narrow, limiting the brain’s blood supply. These changes can affect your ability to add new information into memory and retrieve information that's already in storage. But these age-related changes mainly affect speed: when healthy older adults are given extra time to perform thinking and memory tasks, their results are on a par with younger people.

On the plus side, the connections between distant brain areas become stronger as we get older. These changes enable the ageing brain to become better at detecting relationships between diverse sources of information, capturing the big picture, and understanding the global implications of specific issues. Perhaps this is the foundation of wisdom! It’s as if, with age, our brain becomes better at seeing the entire forest but worse at seeing the leaves.

While these sorts of subtle changes to the brain and mental function are considered a completely normal part of the ageing process, dementia is not and is not part of healthy ageing.

In unhealthy or abnormal ageing, the mental decline is much more severe and may include other thinking abilities, such as rapid forgetting or difficulties navigating, solving common problems, expressing yourself in conversation or behaving outside of social norms. 

Mild Cognitive Impairment

What we call “mild cognitive impairment” is the stage between the expected changes to mental function that we see in healthy ageing and the more serious mental decline of dementia. People with mild cognitive impairment have more pronounced mental decline than would be expected for their age and education. But the symptoms are not severe enough to interfere significantly with daily life, and so are not diagnosed as dementia.

Mild cognitive impairment is characterised by problems with memory, language, thinking or judgment. If you have mild cognitive impairment, you may be aware that your memory or mental function has "slipped." Your family and close friends also may notice a change. But these changes aren't severe enough to significantly interfere with your usual activities.

People with milld cognitive impairment are more likely to develop dementia than people who are ageing healthily. Between 5 and 20% of people aged over 65  have some form of mild cognitive impairment, but only about 10-15% of them will go onto develop dementia - usually Alzheimer’s disease. 

Although mild cognitive impairment increases someone's risk of developing dementia, not everyone with it will get worse and develop dementia. Some people with mild cognitive impairment remain stable over time and some actually improve, no longer having any problems, and return to healthy ageing. The outcome will generally depend on the cause of the mild cognitive impairment.

In some people with mild cognitive impairment the brain diseases that cause dementia are already established. These diseases are not generally reversible and so, in time, symptoms will worsen and their condition will progress from mild cognitive impairment to dementia. For example, some people with mild cognitive impairment have mild memory loss that gradually gets worse, and are to go onto to develop Alzheimer's disease as their memory worsens.

Some people’s symptoms will remain stable and they can live a perfectly functional life that doesn’t interfere with daily activities.  And some with mild cognitive impairment will have a different, often treatable, cause. This could include depression, anxiety or stress. The same symptoms could also be caused by a physical illness, poor eyesight or hearing, vitamin or thyroid deficiencies, or the side effects of medication.

Unfortunately, we can’t yet identify the people with mild cognitive impairment who will go onto develop dementia. And there are currently no treatments available for mild cognitive impairment. But are they’re are many dementia prevention strategies that you can adopt, which we’ve covered on the podcate before. 


So what do we actually we mean by dementia? Dementia describes the symptoms that occur when the brain is damaged by diseases, not by ageing. It affects memory, thinking, decision making and social abilities severely enough to interfere with daily life.There are actually 100 different types of dementia, but by far the most common is Alzheimer’s disease. Vascular dementia, Lewy bodies Dementia and Front-temporal dementia are three of the most common forms of other types of dementia.

These diseases can cause a significant decline in a person's mental abilities. Although 50 million people in the world, have dementia, it is not an integral part of healthy ageing. For a diagnosis of dementia, the decline in mental abilities must have become severe enough to significantly affect and interfere with daily life and activities.

So I hope I’ve managed to convince you that the signs and symptoms we see in dementia are not a normal part of healthy ageing, they are caused by different brain diseases. As part of healthy ageing, some mental abilities, like memory and attention become worse and slow down, while some others may actually improve. Mild cognitive impairment is the stage between the expected changes to mental function that we see in healthy ageing and the more serious mental decline of dementia. And for a diagnosis of dementia, the decline in mental and physical abilities must have become severe enough to significantly affect and interfere with daily life and activities.




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