Dementia a summary term for disease related processes that interfere with normal brain functioning.
Dementia is a progressive disease that causes irreversible damage to brain cells and function- it presently is incurable. Notwithstanding, treatment is available, and therefore it is important get diagnosed early on to gain the most benefit from therapeutic intervention.
There are different types of dementia, the most common of which is Alzheimer’s Disease. Major types of dementia include:
- Alzheimer’s Disease
- Vascular dementia
- Parkinson’s Disease dementia
- Frontotemporal dementia
The clinical/ behavioural expression of dementia-related brain changes, that is dementia symptoms, include difficulties in thinking (e.g., decreased memory, reasoning, orientation) and social functioning, which typically result in a decrease to complete everyday activities independently. However, it is important to realize that there is no simple one-to-one relationship between dementia related brain changes and the development of dementia symptoms. This means that people’s brains can show the signs of dementia -related disease changes without experiencing dementia symptoms as shown in the famous nun studies by Snowden: http://dementiacareinternational.com/2007/03/the-nun-study/
The fact that there is no one-on-one relationship between the disease-related brain changes commonly associated with dementia symptoms is thought to be due to a person’s cognitive reserve.
Before diving into what is ‘cognitive reserve’, let’s just look at whether everyone eventually will develop dementia related brain pathology (i.e., disease related changes). The answer to this question is a sound ‘No’. But it seems that very few people do not develop pathological brain changes (although I have no data to back this statement up). The question is how many people actually develop dementia-related brain changes as they get older (let’s call them group 1) versus how many of these group 1 people show actual symptoms, and how are the two groups (those exhibiting symptoms versus those not exhibiting symptoms despite brain pathology) different. What are people who do not develop behavioural dementia symptoms (e.g., no thinking difficulties) are doing differently. We call such differences ‘protective factors’, factors that decrease the probability of developing the behavioural expressions of the disease, i.e. symptoms.
One of these factors is related to cognitive reserve. Cognitive reserve relates to a the brain’s ability to continue to function despite attacks on it from disease-related brain changes- factors that increase a person’s cognitive reserve include education, remaining mentally stimulated, active, and curious. You can read more on cognitive reserve here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3507991/ Thus, these factors would be considered protective factors.
As mentioned above, not everyone will develop dementia, and in addition to protective factors, also risk factors have been identified. Risk factors are those that increase a person’s risk to develop dementia. Protective factors usually refer to preventive strategies that people can engage in to reduce the risk of developing dementia.
Risk factors include
- high blood pressure (hypertension)
- diabetes (type 2)/ obesity
- physical inactivity
- lower levels of education
- social isolation
Protective factors include
- regular physical activity
- remaining mental active/ stimulated
Practical information on how to implement your very own dementia prevention strategies, and what to keep in mind, you can read here: https://mindyourbrain.com.co/aging/brain-health-and-cognitive-health/
Unfortunately, not enough is known about modifiable risk nor preventive factors regarding dementia prevention despite the concerns of an increasing aging population. As a result, the Canadian government has released its Dementia Prevention strategy in June 2019, which you can access here: https://www.canada.ca/en/public-health/services/publications/diseases-conditions/dementia-strategy.html#s4.3
Another important point relates to the fact that dementia-like symptoms can be caused by many other diseases and conditions that lead to so-called “pseudo-dementia”. In these cases, different underlying causes lead to changed brain function that affects a person’s behaviour. It is important to distinguish between these two types of dementia: true dementia and ‘pseudo dementia’, because treatment is different, and can lead to complete recovery in ‘pseudo dementia’, provided that the causal factors are properly identified and treated appropriately by a professional (e.g., medical doctor).