As we already know, an optimal state of physical and mental health acts as a preventive factor against the cognitive deterioration experienced with age. When we refer to the type of factors that prevent deterioration, we often refer to a concept called “reserves.” But … what do we know about cognitive reserve and brain reserve? What is its influence in the face of deterioration?
In the next article we will discuss the types of reserves available to our brain and explain their contribution as a preventive factor in the face of deterioration.
The brain reserve and cognitive reserve
Reserve capacity allows the brain to cope with changes due to normal aging or neuropathological processes delaying the onset of clinical symptoms.
According to Arenaza-Urquijo and Bartrés-Faz (2013) there are two interrelated theoretical models for the study of the reserve:
1. Brain reserve model
This type of reserve corresponds to the passive model, which refers to the anatomical potential of the brain: brain size, number of neurons, synaptic density, etc. This type of reservation poses a static and invariable model, since it emphasizes genetic and anatomical factors.
2. Cognitive reserve model
It corresponds to the active or functional model, referred to the individual ability to use cognitive processes or pre-existing or alternative (compensatory) neural networks to optimally perform a task. Because this reserve can be increased due to the influence of various environmental factors that we expose ourselves throughout life (they will be explained later), it could be said that this model, unlike the previous one, responds to a dynamic character
What is the influence of the reserve on aging?
Now that we know both types of reserves, we will explain their contribution to the aging process, be it normal or pathological.
Brains that have a high degree of reserve have a greater base substrate, which will allow them greater resistance to brain damage in the face of pathological phenomena or during aging, thus favoring a prolongation of the preclinical state in the processes of predemen- dementia (Arenaza-Urquijo and Bartrés-Faz, 2013).
In terms of normative aging, higher reserve estimates will correspond to brains that are more structurally preserved.
Through neuroimaging techniques such as anatomic magnetic resonance, we can detect brain changes in people with high cognitive reserve that can serve as indicators of a pathological disorder in old age before it has manifested clinically, such as in the disease of Alzheimer’s.
The cognitive reserve refers to the cognitive processing capacity. Such a reservation allows the use of neural networks in an effective way, trying to reduce the impact of the changes associated with aging and neuropathological processes. It could be said that the cognitive reserve potentiates interneuronal plasticity and connectivity.
Through various investigations it has been shown that a high cognitive reserve acts as a preventive factor in the face of deterioration and, in the case of dementias, it will generally delay the onset of symptoms, and consequently, the diagnosis. However, the underlying pathological progress will be the same regardless of its cognitive reserve, therefore, the symptoms will appear when the pathological process is more advanced and, consequently, the progression of the disease will be faster once the threshold has been exceeded. of clinical and cerebral involvement.
“This is due to the fact that a brain with high cognitive reserve will have more facility for the use of alternative neural networks when the networks normally used are damaged, however, this compensation will end when the neurodegenerative disease becomes more severe.”
Regarding normative aging, the cognitive reserve supposes a better performance, a more functionally efficient brain, for this reason it is important to maintain activities that stimulate our cognitive functions throughout life. In several studies, high levels of mental activity have been associated with up to 50% less risk of developing dementia.
Therefore it is essential to consider cognitive training as an intervention to minimize the risk of suffering cognitive impairment associated with age and / or dementia. Likewise, it has been shown that there are also other types of environmental factors that contribute as a protective factor against cognitive decline, such factors are: the state of physical and mental health, occupation, sleep hours, food, activities of leisure and the maintenance of social relations.
We can analyze this type of reserve through functional magnetic resonance imaging (fMRI) or positron emission tomography (PET).
It has been shown that reserve capacity acts as a protective factor against the manifestation of brain changes underlying the aging process or the disease tolerating greater damage to their brains and minimizing, in turn, the impact of the disease on its clinical manifestations.
This fact is of great importance since, although the underlying process is the same, the patient will maintain a quality of life for a longer time. The reserve, therefore, turns out to be one of the numerous factors that demonstrate the reason for the interindividual variability in terms of the symptomatic manifestation before the same cerebral affectation.
Therefore, it is interesting to highlight the need to carry out future research focused on the exhaustive study of specific activities that contribute to increase the cognitive reserve and analyze its consequent interaction with biological factors.