Courtesy The Island

BY Dr B. J. C. Perera
MBBS(Cey), DCH(Cey), DCH(Eng), MD(Paed), MRCP(UK), FRCP(Edin), FRCP(Lon), FRCPCH(UK), FSLCPaed, FCCP, Hony FRCPCH(UK), Hony. FCGP(SL)
Specialist Consultant Paediatrician and Honorary Senior Fellow, Postgraduate Institute of Medicine, University of Colombo, Sri Lanka.

It is a well-known fact that many organs of the human body have some reserve quantum to fall back on during situations where a human being is taxed above its usual calm existence. An excellent example of this is the human heart. In the resting status of the body. the heart beats at around 70 to 80 beats per minute. During strenuous exercise this rate could automatically go up to about 150 or even 200, bringing the reserve power of it into play. The cardiovascular reserve can go up to several times its usual tranquil capacity whenever called upon to provide that extra power.

The notion that the human brain too has fall-back reserve power is a thing that that may surprise many people. As most of us know, we associate the brain with the higher functions of the mind where intelligence and many other cognitive features associated with it make the Homo sapiens to be quite different and differentiate humankind from all other species of the animal kingdom. Yet for all that, with advancing age, impairment of memory is a thing that most people worry about.

By age 60, more than half of adults have concerns about their memory. However, minor memory lapses that occur with age are not usually signs of a serious problem, such as Alzheimer’s disease, but rather the result of normal changes in the structure and function of the brain. However, major and progressive memory loss is a devastating problem for the elderly. Yet for all that, we differ from each other in the way our thinking skills age. One explanation is that some people have better resilience to the effects of ageing because they have developed a better capacity or ‘reserve’ to cope with the changes in the brain that occur with age.

The intellectual power that we can fall back on is referred to as cognitive reserve. Cognitive reserve is the mind’s and brain’s resistance to damage of the brain. One could also rather loosely equate this phenomenon to the ability of the brain to improvise and find alternate ways of getting a job done. It reflects how agile a brain is in pulling in skills and capacities to solve problems and cope with challenges. It is a phenomenon that has to be nurtured and strengthened by learning and experience right throughout a lifetime. Cognitive reserve is developed by an era of education and curiosity right throughout life.

The impression of such reserve power of the brain was first realised and then explored in the late 1980s. That concept which was labelled as cognitive reserve originated when researchers described individuals with no apparent symptoms of dementia or deterioration of the higher functions of the brain who were nonetheless found at autopsy to have brain changes consistent with advanced Alzheimer’s disease. Such observations suggest that there does not appear to be a direct relationship between the degree of brain changes in any given individual and the outward signs of those changes that manifest as loss of cognitive functions.

It was then postulated that these individuals somehow did not show symptoms of the disease while they were alive because they had a large enough cognitive reserve to offset the damage and enable them to continue functioning as usual. The concept of reserve accounts for individual differences in susceptibility to age-related brain changes or Alzheimer’s disease-related pathology. There is evidence that some people can tolerate more of these changes than others and still maintain function.

This curious phenomenon led to intensive research that has shown that people with greater inherent cognitive reserve are better able to stave off or even keep at bay, the symptoms of degenerative brain changes associated with dementia or even some other brain diseases, such as Parkinson disease, multiple sclerosis, or a stroke. A more robust cognitive reserve can also help one to function better and for longer even when one is exposed to unexpected life events, such as stress, surgery, or toxins in the environment. Such circumstances demand extra effort from the brain, somewhat similar to requiring a car to engage another gear.

Research suggests that our level of intelligence, which traces back to childhood as well as our set of lifetime experiences, helps to build cognitive reserve and may account for differences in cognitive reserve between different individuals. The lifetime experiences include education, having an engaging occupation and taking part in stimulating activities; the latter ideally combining leisure activities, learning and social interactions.

The evidence that lifetime experiences help to build cognitive reserve comes from studies of large groups of people over long periods. Such studies have repeatedly found that these life experiences are associated with a slower rate of cognitive decline in normal ageing and reduced risk of developing Alzheimer’s disease.

In other words, higher attainment and engagement appear to protect cognitive function in ageing. Indeed, some studies have suggested that these life experiences may reduce the risk of Alzheimer’s disease by 35-40%. The changes in the brain that are seen in the disease may still occur, but these people cope better and will not ever be diagnosed because they do not present with any symptoms.

The basic perception of cognitive reserve suggests that the brain actively attempts to cope with brain damage by using pre-existing cognitive processing approaches or by enlisting compensatory mechanisms. This would allow an individual with higher cognitive reserves to handle it better to enable the individual to better cope with the brain damage than another with lower cognitive reserves.

It has now been realised that cognitive reserve can be enhanced by a programme of cognitive fitness. Such an initiative would develop the ability of the brain to deal with and function normally when it is induced to call upon the reserve power, especially when disease states take their toll. The very heart and the central cog of a coordinated brain health and cognitive fitness programme involves rather simple but all too familiar lifestyle changes. The cognitive reserve hypothesis gives hope that exposure to various sorts of stimulating activities can help us age successfully. It also leads us to ask what people can do to help increase their cognitive reserve.

It is still unclear what the exact ‘recipe’ for this is. The evidence from studies of large populations suggests that it is exposure to the experiences and activities discussed above across the lifetime that contribute to the reserve, but we do not yet know what specific activities would slow the rate of cognitive decline or reduce the risk of dementia.

Researchers at Harvard Medical School have identified six cornerstones to any effective brain health and cognitive fitness programme. These are as follows:-

Task 1:

Eat a plant-based diet. This is beneficial in many ways and building up cognitive reserves is just one of them. The diet needs to be a good balanced one to supply all macro and micro nutrients.

Task 2:

Exercise regularly. Like the vegetarian diet, this too has a multiplicity of positive benefits. Building up cognitive reserves is just one of them. The nature and severity of the exercise needs to be individualised. Some medical advice would certainly help in that venture.

Task 3:

Get enough sleep. It is well-known that sleep facilitates tissue repair. It is perhaps the same with the neurones and their connecting meshworks as well. A minimum of 6 hours is essential and it is quite good to have 8 hours of quality sleep.

Task 4:

Manage your stress. It has been proven that stress has deleterious effects on many systems of the human body. It is perhaps the same with the brain and the neural tissues.

Task 5:

Nurture social contacts. Good social connections may provide mental stimulation through complex interactions with others and hence build cognitive reserve and maintain healthy cognitive function. This is a very important component of the cognitive fitness initiative.

Task 6:

Continue to challenge the brain everyday. Just as much as regular exercise improves the physical functions and the physical strength of the body, mental exercises are well-known to be beneficial for the proper functioning of the brain. Research studies suggest that doing cognitive tasks that feel difficult, like problem-solving, learning something new, reading a newspaper article and discussing it with a friend, etc.., truly challenge the brain.

This multi-pronged plan includes and integrates proven approaches to committed changes being made in everyday lifestyles. It is advocated that by incorporating simple, specific changes into a daily routine, one could add years of enduring mental stamina and vitality. It is extremely important to realise that these factors are equal parts of a cohesive plan and that they do not work very well in isolation or when they are taken up just as one or two separate efforts. For example, simply eating more fibre or adding a morning walk to your routine is not enough to forestall mental decline. Instead, diet, exercise, sleep, stress management, social interaction, and mental stimulation, all work in harmony, just like in a concert, to yield the desired results.

All that we have undertaken during a lifetime of this worldly experience certainly helps in building up a mental and neurological reserve to enable us to successfully navigate through the drastic effects of age on our mental faculties. There is emerging evidence that even in older ages, commitment to the cause of enhancing that cognitive reserve would certainly help. Old age then becomes a really great pick-up or fizz time.

So, let us go for it.., everybody !!!

The author is grateful to his friend, Professor Nalaka Mendis, for rekindling the writer’s interest in Cognitive Reserve.