We live in a world with an ageing population. That can be a good thing, as it means that the total population is beginning to reduce, which is crucial if conditions on the earth are to continue to be conducive to our survival. But I am very much aware that the adjustment to a smaller population is going to have many difficulties. A big problem is how to ensure that older people existing now will be looked after with fewer young people to support them. That is a very narrow consideration given all the other problems we have coming, like climate change, AI, and the environment. But I do want to focus on the elderly here, especially the common disease specific to them – dementia
Many people in their seventies and early eighties worry about getting dementia. We see our family members, and our friends and acquaintances suffer from it, and indeed we often become carers. We hear about difficulties in dementia provision, and the cost of it. So each time we fumble for a word, or a name we really should know, each time we go into a room and forget why we went there, each time we forget an appointment, we wonder – is it my time now?
The good news is that these examples do not necessarily mean we are developing dementia. It is an unfortunate fact that as our brains age, the connections within them tend to wither away due mainly to failure of the myelin sheaths around the nerve fibres. So older folk may not be as quick on the uptake as they were when they were younger and it is entirely normal to see some reduction in memory skills as we age. There is no hard-and-fast rule when it comes to what kinds of forgetfulness indicate something more serious than typical age-related memory loss, but if it appears to be getting worse very quickly and is impacting on people’s ability to function, then that is a red flag for a diagnosis of dementia. Repeating yourself, without awareness, is also a reliable sign especially if it is getting worse.
I’m sure we all know some “superagers” (1) that is persons 80 years and above with memory performance that is on par with persons in their 50s and 60s. They seem to defy the odds and show no deterioration at all. They have larger cerebral cortices and hippocampi, both areas of the brain associated with memory, and scientists are now working to unravel the neural basis of their recall abilities. But so far they haven’t come up with anything other than the well known factors, although they are doing a lot of excellent research. So what can we do to try to get ourselves into that small group of people who never show signs of dementia? There have been many studies, and there is a lot of advice.

First, make sure you are intelligent to start with (!) and get yourself properly educated and keep educating yourself throughout your life. Super-intelligent people do get dementia but if the brain’s pathways are on top form there is a lot of reserve of brain power that can be used to compensate when some areas get destroyed by dementia. This is called cognitive reserve and is a combination of dense neural networks and structural capacity developed from a lifetime of active engagement, education, and curiosity. (2). Being bilingual definitely increases cognitive reserve. However when intelligent people eventually run out of this reserve the disease can progress more rapidly. A recent study (3) suggested that intelligence is the factor that protects against getting Alzheimer’s the most, but education and life long learning can also help.
Learning a language, playing an instrument or singing keep the pathways whirring away for a long time. Doing puzzles, games and reading a lot can help. Specific cognitive training has also been found to have some effect in preventing dementia, but it seems to have to be a lot of training and not a lot is known about how much you need. Speed training also shows promise (4). There are some supplements that have been shown to slow deterioration, but only in the short term. (5)
Lifestyle changes can make a lot of difference, such as: not smoking, healthy diet, plenty of exercise. Physical inactivity is widespread in rich countries, and in theory is easily remedied. A healthy lifestyle affects brain plasticity in both humans and animals, and can improve mood and brain function. Group sports, swimming, golf as well as walking everywhere and climbing stairs even when you don’t need to, will get your whole body working well into the future. I saw a cartoon once, when a hand written sign was placed at the bottom of a long flight of stairs. It said “FREE GYM”. You don’t have to walk 10,000 steps a day. It is far too time consuming. But a step count of about 5,000 steps a day is easily manageable and helps both your body and your brain. Studies show that any amount over 3000 steps will help if done regularly.(6) It is best to alternate periods of fast and slow walking to get maximum benefit.
But the consensus in one study (7) is that it is by being sociable and keeping your links with your friends in good order that far outweighs anything else you can to keep your brain healthy. There is a vast army of retired people who volunteer with agencies providing help to elderly people, and it might do them as much good as it does the recipients. People who are deaf are far more likely to suffer from dementia if their deafness means they can’t communicate well. So if you suffer from deafness make sure you use your hearing aids and remember to charge the batteries! Another problem is that, as you age, your friends tend to die, so you may have to find new ones, probably younger ones. So join new groups, take up new activities to keep you active.
There is a new study that indicates that it might be important to change to a healthy lifestyle in middle life rather than wait until you are 60. 8 This is because scientists have shown significant transformations of connectivity between 40 and 65 that can alter one’s cognitive abilities for years to come. So it’s important to measure the basics – especially checking blood pressure, cholesterol and blood sugar in midlife, if you are concerned about the risk of dementia. High levels of these can definitely increase the risk, of vascular dementia ,especially. Scientists have also looked at people between those ages to measure the presence of the misfolded amyloid-beta and tau proteins thought to cause Alzheimer’s disease long before symptoms appear. They have also looked at using biological aging tools, MRI pace-of-ageing scans to predict Alzheimers, But until there is a definite treatment to stop progression of Alzheimer’s not many people are going to want these tests, yet.
One thing that stays with you late when you have dementia is the ability to play a musical instrument. This is because it is an automated task that we do without thinking, like typing or riding a bicycle, and this sort of task is done by the cerebellum and basal ganglia, which are resistant to the processes causing dementia. I have seen many examples of this. At one time I played string quartets with a well-known brilliant mathematician who was also a good viola player. He was able to continue playing for a long time while other memories faded, as long as the music was put in front of him and he was told what to play. He only had to stop playing when he couldn’t remember which way up to hold his bow, and he died not long after that. Another lady who was an accompanist continue to play for her pupils, and played with all the feeling and expression she had always used even when her other skills had long gone. Also, processing music fires up regions across both hemispheres, and so evades the damage caused by localised disease. And familiar music will still provoke those strong emotions that were there when first held, late into the disease, which can be used as therapy to remember their former lives.
Nearly all dementias include some degree of memory loss for recent events. Long term memories and a sense of self are generally retained until the final stages in most cases. This is because the process of storing old memories happens in a different part of the brain. We have to be careful here because to make a memory you have to have a conscious awareness of what you are doing. So many cases of lost objects or forgetting what people say are often due to being distracted or being on autopilot, so that the events never really get stored at all.
How people react as they go through the process of dementia is very variable. It depends on the type of dementia, but also on the the patients original disposition. Some cheerful and sociable people lose their memories but retain their ability to relate to people, but others in my experience get very anxious and then go through difficult behaviour changes. The problem is, that the disease itself causes behaviour changes, such as loss of impulse control and and these can be difficult to manage. Each form of dementia has different ways in which they affect behaviour so they have to be considered separately.

Causes of Dementia.
I wrote a lot on the commonest causes of dementia, Alzheimer’s disease, and vascular dementia, in a blog on this site in 2017 (9) so I won’t write very much on those now. But here is some information about other forms of dementia.
One is alcohol-related brain damage, or ARBD for short, and is the only form of memory loss which can be treated effectively. Although it causes severe short term memory problems, it is not a real dementia, and is caused by a vitamin deficiency caused by too much alcohol. I remember it from medical training, when it was called Korsakoff syndrome. Korsakoff was a Russian psychiatrist who first described this, and it was common there because of the East European habit of downing neat vodka ritually. When I was doing my house jobs in hospital there were some Polish doctors who would invite us all to parties, which involved ritual drinking of vodka – apparently a common custom for them at that time. Of course it made me (and my friends) very ill indeed and I never did it again. It must have caused brain damage on a big scale, and Dr Korsakoff looked into it and found the damage was actually due to a vitamin B1 (thiamine) deficiency. Thiamine is a crucial co-factor for three major enzymes that help break down glucose into cellular energy. Without it, brain cells do not have enough energy to function and will eventually die. [1, 2] This causes microscopic bleeding and scar tissue in the areas of the brain responsible for short term memory. Nutrition affects this as well, because people drinking too much alcohol are often malnourished and don’t get enough thiamine in their diet, and alcohol interferes with the liver’s ability to store it and prevents brain cells from properly using the vitamin. There is a possibility that memory loss might stabilise and even improve, if people can stop drinking completely, although that might take three or four years, and most sufferers can’t stop completely.
In contrast, there are several very unpleasant forms of dementia which can’t be treated. Stop reading now if you don’t want to hear about them, but for completeness here they are.
Frontotemporal dementia (FTD) affects younger adults between 45 and 65, often sparing memory in the early stages. It often runs in families -, in 10% of cases it is transmitted as an autosomal dominant, and in 40 to 50% of cases there is a family history of the disease. it is caused by a build up of proteins such as Tau or tdp-43. It can cause profound shifts in personality, and people can disregard social boundaries. They can be emotionally distant and show compulsive behaviours, or severe lack of motivation. Another variety affects language and speech or movement disorders. All varieties are easily misdiagnosed as something else, such as burn out, severe depression, or other neurological problems.
The worst of all is probably Lewy Body disease. It combines the worst elements of Alzheimer’s and Parkinson’s into a single, unpredictable disease. It strips away both mental and physical independence rapidly and carries an average life expectancy of just 5 to 8 years from the onset of symptoms.  Many people are misdiagnosed in the early stages if Parkinson’s symptoms predominate. I personally think the suffering that people with this have must be absolutely awful. They can get terrifying hallucinations and sleep disorders where they act out their dreams which can include violent flailing, punching, or kicking, leading to poor sleep quality and potential injury to themselves or their partners. I had one patient who was admitted to a secure unit because she was harming her partner and others. She had to stay there until she died. This would be something that I would want euthanasia for, not that it would ever be allowed in this country as sadly, by the time the diagnosis is clear the patient would probably not have capacity to give consent.
There are hopeful developments for treatment for some forms of dementia, but none that would make a big difference at this time. Donepezil an anti cholinesterase, has been used for years to manage symptoms and cognitive functions. Many of my patients were prescribed it in the early 2000’s. We thought then than it might slow the progression of Alzheimers, but it didn’t. Recently, 10 Lecanemab & Donanemab have been proven to slow the decline of cognitive function, (11) and to clear amyloid protein but they have big drawbacks such as, having to be used very early in the disease, needing to be given by I/V infusion; they have severe side effects and are extremely expensive. They are not available on the NHS. So there is no magic bullet coming soon to reduce the number of sufferers. There will be more people living longer, and at age 85, one in three will be affected, rising to more than 50% over 90. So my statement at the beginning is a real problem – how will these people be looked after with fewer younger people around?
Japan is the country to look at here, as it has a very high proportion of elderly people. It copes by firstly requiring people to continue to work for longer, and keeping them fit as long as possible. There is a compulsory long term insurance for everybody, and care is heavily subsidized. There is community based integrated nursing and medical care, and Japan makes a lot of use of robots and distance technology, This system reflects the respect the elderly have in the country., Looking to the future, we can imagine that many rich countries are going to find it very difficult to provide this level of care, because of the extreme inequality in wealth that has developed recently. Ultimately if the world economic system does not break down, the problem will be solved, as the bulge of elderly will die, after which a level is reached when the reduced number of young people can cope. One development I would like to see is the expansion of euthanasia – ie the intentional act of ending a person’s life to relieve intractable pain and suffering, for those who decide early on that they would prefer this instead of a prolonged period of suffering. THe UK however is way behind other countries in passing laws to enable it, citing the risks of coercion. Other countries manage it safely though, and the religious lobby has long lost the argument with the general population, and in my view should not be allowed to force their views on those who want it.
In the meantime, those of us in the latter half of our lives should do our best to keep as healthy as we can for as long as we can. And those of us who do get dementia must hope to be treated humanely for as long as we need it. Fortunately, this is still the norm in our society. Long may it continue.

References
1.superagers
https://www.brain.northwestern.edu/superaging/index.html. superagers and https://www.newscientist.com/article/2529259-the-secrets-to-keeping-your-brain-sharp-in-old-age/.
2. cognitive reserve
h3. ttps://www.health.harvard.edu/mind-and-mood/what-is-cognitive-reserve
3. A recent study suggested that intelligence protects most, but education can help.
https://www.alzforum.org/news/research-news/intelligence-matters-more-brain-reserve-education-helps
4 cognitive training can help in the short term
https://www.nih.gov/news-events/news-releases/cognitive-speed-training-over-weeks-may-delay-diagnosis-dementia-over-decades
5 Neuvira https://pubmed.ncbi.nlm.nih.gov/36929344/. neuvira. supplements
6. more than 3,00 steps a day helps prevent Alzheimer’s 
https://www.nature.com/articles/d41586-025-03596-2
7. keeping up your social connections can help prevent alzheimers
https://pmc.ncbi.nlm.nih.gov/articles/PMC5764000/
8 middle aged brain https://www.newscientist.com/article/2526727-why-you-need-to-future-proof-your-brain-in-middle-age-and-how-to-start/?utm_source=nsday&utm_medium=email&utm_campaign=nsday_ukrow_040626&utm_term=Newsletter NSDAY_Daily UK ROW
8a middle age https://www.cell.com/trends/neurosciences/fulltext/S0166-2236(24)00017-1
9 Old age part 4 Sceptical GP
https://scepticalgp.com/2017/01/07/old-age-part-4-losing-it/
10 the role of thiamine deficiency in alcoholic brain disease. https://pmc.ncbi.nlm.nih.gov/articles/PMC6668887/ also [1, 2]
11 https://www.hospitalnews.com/are-we-entering-a-new-era-of-dementia-treatment, new treatments clearing plaques 
https://www.hospitalnews.com/are-we-entering-a-new-era-of-dementia-treatment/