Cognitive disease: what impacts our brain power?

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Image: CC0 Public Domain
Image: CC0 Public Domain

In the case of the brain, it is very much a "use it or lose it" situation. It can be questioned whether those who lead more intellectually stimulating lives, challenging their brains, somehow acquire protection from the mental decline that we believe comes naturally with age. This question does not only stand for age but other insults too, from intoxication and head injuries to strokes, Alzheimer's and Parkinson's disease.

In its 2015 annual report, the Alzheimer's Association estimates that by 2025, the number of people age 65 and older with Alzheimer's will reach 7.1 million -- a 40% increase from 5.1 million aged 65 and older affected in 2015. Furthermore, it is estimated that 6.8 million people die from neurological disorders each year.

The ideology that those who perform better in academia will suffer to a lesser extent from neurological disease than those who do not is controversial. The theory has been described by scientists as "cognitive reserve". This theory suggests that detrimental effects of aging and brain disorders such as dementia will have a smaller impact on those with a large "cognitive reserve" as the brain can stabilise its state without showing signs of mental decline. However, the theory is criticised as being 'common sense' in that those who start off with a higher reserve have further to fall.

This week it was released that in recent years it has become apparent that life experiences modify the way disease expresses itself in the brain. "One study in Toronto demonstrated that people who could speak two languages had later onset dementia," said lead author Dr. Suvarna Alladi, a neurology professor at Nizam's Institute of Medical Sciences in Hyderabad, India. Switching between languages challenges the brain, as it can be harder to find a particular word, this promotes neuroplasticity or "cognitive reserve," which prepares the brain to deal with new challenges, like disease. Many factors are seen to develop our cognitive reserve, some a fundamental pathway in strengthening neurological power. For instance, going through higher education may be critical to compensate for damage or disease.

The theory of cognitive reserve is hardly recent; findings from a 1992 study implied that patients who suffered from Alzheimer's with a higher educational background had something 'padding' their brain. This protected them from the full effects of clinical symptoms that would be expected from the physical condition of their brains. Was this their "cognitive reserve"? Although there is no definite answer, a team of researchers have found that people who are highly educated are better at recruiting alternative neuronal networks to compensate for the deterioration of their cortical regions. These regions are said to compose of three parts: sensory, motor, and association areas dealing with complex behaviour and thought. It is not only the size of the brain, which correlates to the number of neurons, but the wiring of the brain. Epidemiologists have confirmed that people with high literacy and IQ cope better with the progress of Alzheimer's disease. They also recover from stroke and head injury at a faster rate than the average person.

If you want to boost your own cognitive reserve, try mental gymnastics; whether that be through learning to play an instrument, a challenging job, or a crossword puzzle that will build up a reserve of brain cells. Keeping fit will encourage blood flowing to the brain nourishing brain cells with oxygen. Cardiovascular fitness strengthens the brain's executive functions and preserves white and grey matter. Eat well; having a nutritious, well rounded diet gives our brain the best chance of avoiding disease. Although research into diet and brain function is in its infancy, a diet high in grains, oily fish (mono and polyunsaturated fatty acids), vitamin E and certain B vitamins - B6, B12 and folic acid (known to reduce levels of homocysteine in the blood) may slow cognitive decline.

It is a sad fact that our brain's capability of storing new memories, spatial abilities and creating strong neural pathways deteriorates from our early twenties but it is not all bad news; you can begin to train your brain to build cognitive reserve at any age.




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