Age-related cognitive decline occurs for a number of reasons. There is a progressive loss of brain cells (grey matter), so that when you reach the age of 90, on average, one in every 10 brain cells is gone. More important is the loss of nerve fibers and connections (white matter), which may result in you ending up with less than half of what you had in your prime.
More marked changes are seen in some areas of the brain, reflecting local mismatches between supply and demand, protection and overload. This means that some functions, such as processing speed, attention span, working memory and learning, are affected more significantly than others.
For example, as you age, it may take you longer to think through a problem or make a calculation. It may become more common for you to forget the simple things, such as where you left the car keys. At the same time, other things such as vocabulary, past knowledge and skills remain relatively intact. We appreciate these things as ‘wisdom’.
In some individuals, age-related cognitive decline is more severe and widespread, and the ability to function independently is compromised. This is known as dementia and can be the result of accelerated, age-related processes, or superimposed brain damage due to degenerative diseases such as Alzheimer’s or Parkinson’s, or stroke.
A number of factors influence age-related cognitive decline and diet also plays an important role in slowing rates of age-related cognitive decline and dementia.
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