'Where do we stand with dealing with dementia?'

By Denis Sale

AN existential fact now is that as we live longer more people will suffer from conditions associated with the inevitable deterioration brought about by the ageing process. For illustration, in 19th-century England, life expectancy was around 40–45 years, as compared with today, where it’s around 82.8 years for females and 78.8 years for males. As dementia is often associated with the ageing process, it is not surprising that this condition is increasing globally, and especially in first-world societies.

Dementia is a general term for a decline in mental functioning, primarily affecting memory and thinking skills. It is caused by damage to brain cells, leading to difficulty with daily activities and communication. Alzheimer’s disease is the most common cause of dementia, accounting for around 60–80% of cases.

However, it’s important to note that dementia is not a normal part of ageing. Invariably, some memory lapses and cognitive changes are common as people get older, but the exact causes of dementia are complex and not fully understood. Research shows that many other factors contribute to its development, including genetics, lifestyle factors such as diet, exercise, cognitive activities and certain medical conditions such as diabetes and heart disease. What we do know is that dementia involves brain cell damage, especially to the hippocampus, a brain region crucial for memory formation. Damage to the hippocampus often leads to memory loss and difficulty in forming new memories. Also, persons with dementia often have difficulty in clarity of thinking and have problems with language and behaviour.

The knowledge funnel and dealing with dementia

While there is still no cure for dementia, researchers are making strides in developing treatments that can slow the progression of the disease and improve symptoms. For example, several drugs have been approved in recent years that can slow cognitive decline in early-stage Alzheimer’s disease. These drugs target amyloid beta, a protein that accumulates in the brains of people with this condition. A few weeks ago, the national news reported on the drug donanemab, which is a plaque-targeting therapy that helps to slow down the decline in memory, thinking and daily functioning. It works by targeting amyloid plaques, which are clumps of protein that can build up in the brain and contribute to Alzheimer’s disease. However, the cost of the treatment has been estimated be to be around £25,000 annually and was deemed too expensive to be available on the National Health. So, what are potential future scenarios, and what are other useful practices that can mitigate the decline in functions caused by dementia?

An interesting frame is that of Martin’s (2009) depiction of the knowledge funnel. In developing our understanding of the nature and working of things in the world, he depicts a process in which phenomena can move from being a Mystery (experienced in some way but not understood) to a Heuristic (understandable in good part) and finally to Algorithmic (fully understood, predictable and controllable). A highly significant global medical example of moving down the knowledge funnel can be seen in terms of our understanding and subsequent response to the discovery of the Acquired Immune Deficiency Syndrome (Aids). Aids was only formally identified as a new disease in 1981 and remained a mystery until 1983, when the Human Immunodeficiency Virus (HIV), the virus that causes Aids, was discovered. As is well documented, the origins of the virus, as well as the specific means and rates of transmission, evoked much controversy and debate at that time. Also, treatments, despite the initial optimistic hype of azidothymidine (AZT), were controversial and driven more by desperation rather than hard science, which, in context, was understandable. Today, HIV is clearly in the realm of heuristics, in that we have a comprehensive understanding of the behaviour of the virus and its impact on the immune system, as well as how to mitigate its most deleterious effects – in an increasing number of cases – to the progression to full-blown Aids. At present, our knowledge is not algorithmic, as this level of knowledge would require both a sterilising cure (where the virus is completely eradicated from the body), as well as an effective vaccine. However, as Avert (2019), which provides global information on HIV and Aids, summarises: “There is no cure for HIV, although antiretroviral treatment can control the virus, meaning that people with HIV can live long and healthy lives. Most research is looking for a functional cure where HIV is reduced to undetectable and harmless levels in the body permanently, but some residual virus may remain.”

In the present context, people with HIV who have access to the best medication and care can live to the normal population lifespan. In this context, there is hope for further significant progress for dementia sufferers. Perhaps the most useful knowledge now is that research shows that lifestyle changes can be positively impactful in mitigating cognitive decline and thereby enhancing aspects of wellbeing. In this column, I focus on the powerful impact that exercise (both physical and cognitive) can have on dementia, as this is a practical and viable course of action for many people.

The pioneering work of Wendy Suzuki

Wendy Suzuki is a world-renowned neuroscientist who, having experienced her father’s suffering from Alzheimer’s, was passionately motivated to understanding the basis of such cognitive decline at the neurological level, and potential ways to prevent its onset. She focused on the hippocampus – for the reasons noted earlier – as it is particularly vulnerable to decline in neurodegenerative diseases like Alzheimer’s, which lead to memory loss and cognitive impairment.

Suzuki found that exercise could positively impact brain health and potentially slow down cognitive decline. Her research has shown that regular physical activity can lead to increased neurogenesis (the birth of new neurons) in the hippocampus, which may contribute to improved memory and learning abilities.

This is particularly interesting as we now have a significant body of evidence to suggest that our brain has the capability for neuroplasticity. Neuroplasticity is the brain’s ability to change and adapt throughout life, which means that it can form new connections, reorganise existing ones and even grow new neurons in response to learning, experience and injury. This remarkable property enables us to learn new skills, recover from brain damage and maintain cognitive function as we age. Certainly, the hippocampus is well known for its ability to generate new neurons, and recent research (eg Alvarez-Buylla, 2024) even suggests that neurogenesis may occur in other brain regions as well, albeit at lower rates.

Suzuki’s research on the impact of exercise on the hippocampus has provided specific details relating to how exercise impacts key areas of brain functioning. Most significantly, regular exercise has been shown to increase both neurogenesis and the volume of the hippocampus, especially in older adults who are at risk of cognitive decline. This enhanced neuroplasticity improves various cognitive functions associated with the hippocampus, including memory consolidation, learning new information, attention and decision-making. Memory and thinking are very much related in terms of cognitive processing – one could say they are two sides of the same coin – and this is good for maintaining cognitive functioning and mental health.

In summary, Suzuki’s research highlights the importance of incorporating regular exercise into our lives to maintain and improve not only physical health but also psychological health in key areas of cognitive functioning. Even moderate amounts of exercise, such as 30 minutes of brisk walking most days of the week, can have significant benefits for the hippocampus. So, let’s keep our hippocampus in good size and “fluffy”, to use Suzuki’s metaphor. Of course, keeping mentally active and learning new things as we age also adds to the exercise portfolio of benefits.

• Dennis Sale worked in the Singapore education system for 25 years as adviser, researcher and examiner. He coached over 15,000 teaching professionals and provided 100-plus consultancies in the Asian region. Dennis is author of the books Creative Teachers: Self-directed Learners (Springer 2020) and Creative Teaching: An Evidence-Based Approach (Springer, 2015). To contact Dennis, visit dennissale.com.