Over the hill

As far as the structure of your grey matter is concerned, once you're past your mid-twenties, it's downhill all the way. Your brain actually begins to shrink. But that doesn't mean that brain function peaks in its mid-twenties. In many regards several cognitive abilities actually become more efficient as you age, despite the structural degradation. In this regard, a better system of wiring is more important than having more wires.

Throughout middle age and beyond, the branching antennae (dendrites) that pick up signals from other neuronal brain wires progressively retract and lose the spiny tendrils that are studded with synaptic connections. The exception to this rule being the neural pathways involved in mental activities that you regularly challenge your brain to tackle. This helps to ensure that the relevant synaptic connections are maintained. Unfortunately, whatever you do, the myelin wrapper around the wires that speed up electrical transmissions will gradually lose its integrity, this part of the process starts to kick in during your forties.

These processes all lead to a thinning of your cortex – the outer layer of your brain within which billions of wires share their electrical information across your ever diminishing numbers of synaptic connections. As a consequence of all this brain shrinkage, the valleys at the surface of your brain get wider, the peaks get narrower and deep inside, the fluid-filled spaces (your ventricles) become larger. And, to add insult to injury, your neurotransmitter systems, the chemical messengers that cross the gap (synapse) between the end of one brain wire and the beginning of the next, become incrementally less efficient as each day goes by.

This gradual decline is inevitable and an inescapable fact of life. If we all lived to be 150 years old, we'd all display obvious signs of Age Related Cognitive Decline (ARCD) as a result of these natural processes of brain aging. Being around that long would mean that at some point we would all have succumbed to the forgetfulness, distractedness and compromised problem solving that characterizes ARCD.

Sadly, for many people ARCD kicks in far too early on in life. Whilst some people still function just fine well into their nineties, only starting to show signs of decline as centenarians, for others it can begin to interfere in the tasks of daily life much sooner – perhaps even in their forties or fifties.

We've all encountered it. Whether it is someone who constantly forgets that they've already told you their favourite story many times before, a person getting lost on a journey they have completed on numerous occasions, or an elderly relative who always calls you by the wrong name.

Witnessing cognitive decline in someone else can be one of life's most harrowing trials, but for the person actually experiencing it, well that's something else altogether. The transition from strength and vigour to weakness and frailty is tough enough to deal with, but lacking the capacity to care for your own needs, not to mention the loss of dignity associated with losing your independence, can be devastating.

ARCD may be an inevitable thing in the long run but there is, you'll be pleased to hear, some good news. The speed at which its processes unfold varies greatly from person to person. In many cases, inherited genetic conditions notwithstanding, it seems that these differences are largely to do with factors over which you can have significant control. Rather than abandoning yourself to fate, you can instead establish what you can do to hold onto your marbles for as long as possible – and then do something about it.

The really great news is that many of the things you should be doing to ensure you maintain a healthy brain for as long as possible are enjoyable activities. Activities that get you out and about, that involve interacting with other people and generally having a good time.

Putting the brakes on

Thanks to the incredible advances in medicine, life expectancy continues to lengthen. It's great to know that we're all likely to be around a lot longer, but being around longer also means that our chances of experiencing ARCD are also increased. This leads to the billion dollar question: what can each of us do to hang on to our marbles for as long as possible, right up until the day we do finally conk out?

Well, there are several things that we can all start doing right now. Many of them are simple things that we've already covered in this book, which unless you've skipped straight to this chapter you are already aware of. Out of all the practical bits of advice, there are two highly effective brakes that you should seriously consider applying sooner rather than later, if you haven't already done so, to slow your descent into ARCD.

Brain attack

Although heart attacks are pretty common and fairly well understood, most people seem to be unaware that the same process can also take place in the brain. This is why a high dietary intake of saturated fats is associated not only with a high incidence of heart failure, but also with a high incidence of stroke. If a heart attack is the name for the situation whereby the blood supply to a certain chunk of heart tissue is cut off and the tissue stops functioning properly, then a stroke might be better described as a “brain attack” because it is exactly the same problem but with a different organ.

A body of evidence is accumulating to suggest that the symptoms of cognitive decline are caused by a series of tiny undetected strokes that occur throughout life. “Silent Cerebral Infarcts” as these mini-strokes are known, may also play a role in causing migraines when they damage the white matter that ferries electrical information from one part of the brain to another. Our only hope of protecting ourselves against this is healthy blood flow.

If the threat of a heart attack doesn't make you give that double sausage, double egg, chips and fried bread breakfast feast a miss, then maybe the equally likely threat of a brain attack will make you think twice. Again, it doesn't mean you should completely cut out eating your favourite fry up but if you can, try to make a habit of eating foods low in saturated fat, with the occasional celebratory gastronomic blow out now and then.

Brain change activity

Avoiding saturated fats and toxic smoke to keep the blood vessels wide open and flexible is only half the story. The reason that regular exercise is so good for your brain as well as your health in general is that it strengthens your heart. Eating healthy food (fruits, vegetables, fish, nuts, herbs, spices, pulses, lentils and wholegrain cereals) ensures that your blood is filled with nutrients. If the very pump that distributes this nutrient rich broth to every cell in the body is strong then it will reach every nook and cranny of your brain. Your brain is constantly in need of raw nutrient materials to build new connections, create new neurotransmitters, carry out maintenance on its wires and keep the myelin go-faster wrappers of those wires in a state of good repair.

If your heart is allowed to fall into disrepair by, for example, driving instead of walking or by never getting around to spending half an hour getting out of breath every other day then it will become weaker. So when it comes to keeping every part of body and brain fully stocked with all their basic requirements, it will fall short, it will fail to deliver. It's as simple as that.

It's never too late, but the older you get the more vigilant you need to be in terms of eating healthily and exercising regularly. Decades of self-abuse can be turned around and, indeed, the weaker your heart has become the greater the benefits you will perceive once you start making the lifestyle changes necessary to strengthen it. You'll have more energy and you'll feel more motivated to get out there and do something that's active, sociable and hopefully mentally stimulating. The result being that once you are out there doing it, you'll find that your mood will naturally improve, you'll be inspired to do it more and you'll be more open to trying out new activities.

This new found drive to take part in a range of different activities will, if you participate regularly enough, stimulate reinforcement of the connections between all the different brain areas involved in carrying out those activities. And, if they are sufficiently stimulating, they will even help you build something called cognitive reserve that can keep dementia at bay for longer. Physical activity is the key to a healthy heart – which is, quite literally, the driving force of mentally stimulating, sociable activities that challenge your brain to change.

Building cognitive reserve

The Einstein Aging Study (so named because it was conducted by the Albert Einstein College of Medicine – Albert himself was not involved!) followed 2000 people aged 70 and above who were residents of the Bronx district of New York City for four years. Every year these residents were put through a variety of tests to monitor changes in their physical strength, balance and coordination, along with a wide variety of cognitive abilities. As well as undergoing these tests, images of their brains were captured with an MRI scanner.

The aim was to examine the impact of specific lifestyle choices on the various factors that influence a person's ability to look after themselves, with ARCD high on the list of priorities. Specifically, they were interested to know if there were any particular hobbies, games or social activities that might somehow help to condition the brain to resist the cognitive impact of the metabolic inefficiencies that inevitably crop up as we age.

They found that four activities were associated with a significantly reduced likelihood of developing the symptoms of cognitive decline: playing a musical instrument, playing chess, dancing and reading all seemed to have a positive impact on slowing the rate of cognitive decline. It was noted that none of these activities made the slightest difference to the outcome unless they were practised regularly.

They also found that those who were often socially engaged, who took regular moderate to intense exercise and that participated in the above activities more than once a week enjoyed a much longer period of dementia-free life.

You'll no doubt recall how we previously talked about your brain physically changing to better accommodate any specific behaviour that is practised intensely, regularly and consistently. It should come as no surprise to you that now and then, occasional engagement with the above activities does little to keep dementia at bay.

What's more, all of the above activities are mentally taxing – the other defining feature of activities that actually inspire the brain to make changes. If you don't up the ante in terms of tackling more and more challenging versions of the same activity then the brain will stop making the necessary changes for further improvements. Let's take a closer look at each of the activities:

Playing a musical instrument involves manipulations of an object with various body parts (e.g. fingers, lungs and mouth for most wind instruments) to produce tightly coordinated and rhythmically precise sounds. These sounds must match the desired musical notes that are usually effortlessly translated from visually scanned marks on a piece of paper, denoting the pitch, onset, duration and style of each note. All whilst listening keenly to sounds produced both by oneself to ensure accurate rendition but also in light of others to constantly establish that the desired overall effect is being created.

As you can imagine, all of these processes are extremely cognitively demanding to one degree or another. Hence playing a musical instrument induces changes that enable brain areas in the prefrontal cortex (PFC) to exert better control, through tighter integration, over the many other brain areas that all need to be carefully coordinated to successfully hit the right notes at exactly the right time. It is this dense connectivity between PFC brain areas, that seems to confer the miraculous marble-preserving facility of auxiliary brain networks that take over mental functions that would be otherwise lost when important brain areas are irreversibly damaged by the aging process.

Chess requires potential moves of both players to be imagined and held in mind so that further moves can be thought through and evaluated. Opportunities and pitfalls of each potential sequence of moves must be analyzed to select the best strategy. The more moves in advance a person tries to plan, the harder the brain areas in their Frontal and Parietal Lobes that support working memory (the Hold Line) are pushed, to try to keep in mind where all the pieces would stand after each imagined move.

The harder working memory is put to the test during the day, the more work will be done overnight to reinforce the synapses connecting Frontal and Parietal brain areas to increase its capacity for next time. As we know from a previous chapter, boosting working memory is a very powerful way of increasing IQ as it provides a sturdy foundation upon which problems can be better solved.

Dancing is a quintessentially social event. Maintaining regular social contact with other people is known to have a powerful positive impact on mental health and wellbeing by making individuals feel connected to their community. Most dances bring two humans into direct physical contact, which triggers the release of oxytocin from their Pituitary stop into the bloodstream. This is a neurohormone that induces feelings of trust, comfort and a sense of belonging, again increasing feelings of social connectedness and wellbeing.

The cognitive challenge presented by dancing is no easy one. Your Auditory Line has to create the perception of music and find the beat. Your Visual Lines have to make sense of the dance moves demonstrated by your instructor. The Mirror stop is involved in both observing the actions of others and performing those actions yourself – it is critical to the process of learning skills from others. Your Basal Ganglia stop initiates body movements and must do so in time to the beat of the music. And your Cerebellum has to constantly fine-tune the signals sent to your muscles to maintain balance. All of this must be coordinated with the movement of your dance partner. As well as keeping you light on your feet it also helps to sustain an agile mind. A better whole brain workout you'd be hard pushed to find.

Reading involves converting strings of letters into words, words into sentences and keeping the meaning of one sentence in mind in light of those preceding and following it. Images must be conjured up in the mind's eye, sounds in the mind's ear, tastes and smells in the mind's mouth and nose. Previous chapters of whatever book you happen to be reading must be brought back to mind in order to interpret new events and imagine future scenarios in anticipation of the most likely outcomes. The trajectory of the plot must be tracked whilst a dynamic impression of the characters' personalities is assembled, not to mention the inter-relationships between them and knowledge of what they do and do not know during the intertwining narratives. Fabulous mental gymnastics are performed any time we lose ourselves in a good novel.

Alzheimer's disease versus Alzheimer's dementia

By the time people with Alzheimer's disease-related dementia develop the symptoms of chronic forgetfulness and problems with planning and execution of day-to-day activities, their brains have invariably accumulated a significant degree of damage. The Beta-amyloid plaques and neurofibrillary tangles that appear as dark patches in brain scans were for a long time thought to be what caused the affected brain cells to die off. The latest thinking is that far from being the cause of the trouble, it may in fact herald an attempt to salvage the dying brain cells. Either way their presence signifies, as far as we currently know, irreversible death of brain cells.

This irreversible decline usually starts in the Hippocampus (memory banks – DG and EC stops) and PFC areas vital for the various mental operations that together fall under the banner of “Executive Function” – planning, sustained attention, decision making and the like.

The fantastic news here is that people seem to be able to live a perfectly good and healthy life even when the unstoppable ravages of Alzheimer's disease are well under way so long as they have built up cognitive reserve by regularly challenging their brains.

Redundancy in the brain

Now you know that the key to keeping ARCD at bay is building cognitive reserve. The increased connectivity between Prefrontal brain areas involved in orchestrating attention, planning and problem solving enable any mental operation to be achieved in several different ways. These densely interconnected brain areas can then reorganize to take over functions lost when a certain brain area is permanently compromised through dementia, mini-strokes or head injury for that matter. This accounts for why the more physically and mentally active elderly individuals seem to be able to hold onto their marbles for longer.

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Every day of your life your Cortex loses 85,000 neurons, that's one a second!

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The Columbo effect

One strange factor that seems to be positively correlated with delayed onset of dementia is dental health. It sounds strange, but the better you look after your teeth the better the chances of your brain serving you for a lifetime free of cognitive decline. It is however more to do with the immune system in general than anything specific to do with your gnashers. Elderly people who undergo major surgery or suffer a succession of minor illnesses are more likely to experience accelerated cognitive decline. It would seem that anything that excessively mobilizes the immune system to aid recovery actually accelerates the process of ARCD.

What put researchers on to this possibility was the fate of the wonderfully talented Peter Falk who famously played the shabby, loveable detective Lieutenant Columbo. At the beginning of 2007 he was suffering from mild cognitive impairment but mentally sharp enough to be at work shooting a film, American Cowslip. Sadly, after a series of major dental operations, his cognitive abilities went into a tailspin within just a few weeks.

Another line of scientific investigation also supports the concept that the immune system is very much involved in the development of Alzheimer's. Many middle-aged and elderly people suffer from rheumatoid arthritis. This is where the immune system attacks the joints leading to painful swelling, which in turn eventually causes stiffness of the affected joint. For a long time there was no cure but, in recent times, a new class of drugs called biologics have revolutionized treatment of this condition by eliminating the component of the immune response that causes the inflammation in the first place. Curiously, people that have been on this treatment for many years show an extremely low incidence of Alzheimer's dementia compared to others of the same age and from the same socioeconomic background. Could these drugs also be protecting against immune responses that accelerate cognitive decline? No one yet knows for sure, but it is an exciting possibility.

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Memories are consolidated in your sleep – the better you sleep the more you will remember – people who nap after memorizing information recall more when tested.

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Chapter takeaways

• You might not be able to stop it but you can slow it down. Start applying the brakes now to delay Age-Related Cognitive Decline.
  
  
• Don't let free radicals become a bull in your china shop. Give healthy nutritious foods packed with antioxidants the upper hand, let them play a regular part in your diet.
  
  
• If you want to keep your brain maintained in full working order it's vital you look after the pump that keeps it pumped with everything it needs – your heart.
  
  
• Keep your pipes clear. Take the stairs instead of the lift and when possible, leave the car behind, walk or cycle instead. Give smoking a miss and, if you haven't already done so, reduce your intake of red meat.
  
  
• Stop the rust by keeping your brain's cogs well-oiled and turning smoothly with mind-stretching, rewarding activities.
  
  
• Build cognitive reserve. Whether you're going to learn an instrument, play chess, get up and dance, read, speak other languages, play table tennis or start juggling – do it regularly and keep on doing it for the rest of your life!