Friday, January 6, 2012

The brain's cognitive decline starts at age of 45

A large and long-lasting British study has revealed that our brain's cognitive functions already start to decline at the age of 45. That is much earlier than what previously was hypothesized. Using various testing methods, scientists discovered that the decline affects almost all domains of cognitive performance, such as reasoning, mathematics and memory. Only knowledge of language, our vocabulary, remained intact.

Study design
A total of 10,308 people originally participated in the study, which was set up in Great Britain, but only 7390 people made it into the statistics. Scientists did a 10 year follow-up, in which they measured the cognitive decline that came with the ageing process. Participants were given a set of 65 tests, measuring performance in various cognitive domains, to create a complete picture of the brain's functioning. At the start of the study, scientists made age groups and took baseline measurements.

Cognitive performance for reasoning in the age group 45-49 years was found to be 3,6 percent lower ten years later. Also, scientists showed that older people have faster declining cognitive functions: the age group of 65-70 showed a decline of 9,6 percent ten years later. Other parameters of cognitive function, such as memory, showed a somewhat different figure, though all but vocabulary saw cognitive decline starting from the age of 45.
Graphs showing the cognitive decline in various areas in different ages groups. The measurements show how each age group performed ten years later.
Decline in cognitive function starts earlier than previously assumed. According to the scientists, this highlights the importance of lifestyle choices. Because diseases of the brain that come with age, such as dementia, prove to have a much longer 'incubation time', it matters even more what you do in life. Life expectancy continues to increase, but our cognitive functions do not seem to increase along with it. It shows intervention to keep cognitive performance high is an area of interest for scientists in the coming years. Because we previously thought our brains do not decline in performance before the age of 60, the British study significantly changes our views in this area. 

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