Those who don't engage in complex mental activity over their lifetime have twice the shrinkage in a key part of the brain in old age, according to researchers from UNSW.
The researchers found that people who have been more mentally active over their lives have a larger hippocampus - which relates to memory - and critically that it shrinks at half the rate of those who have lower mental activity.
This is the first time that researchers have compared participants' brains over a period of time in relation to mental activity patterns, adding weight to previous work which shows that complex mental activity helps prevent dementia.
"This is a significant finding because a small hippocampus is a specific risk factor for developing Alzheimer's disease," says the lead author, Dr Michael Valenzuela, from UNSW's School of Psychiatry.
"It also helps throw some light on why there has been this consistent link between mental activity and lower dementia risk," he says.
In this NHRMC supported research, the researchers looked at a group of more than 50 people who were 60 years of age over a period of three years.
Dr Valenzuela says while many drug companies are trying to find a pharmaceutical target to prevent the shrinkage of the hippocampus, the good news is that people can help themselves.
"Our prior research shows the risk for dementia is quite malleable, even into late life," says Dr Valenzuela. "It is vital that everyone is involved in cognitive, social and physical activities in late life such as dancing, tai chi, sailing, travelling and learning a new language, for example."
The paper has just been published in the Public Library of Science ONE medical journal (PLoS ONE).
Dr Valenzuela and other researchers from UNSW, the University of Sydney and James Cook University are now working on a clinical trial to assess whether relatively short-term cognitive and physical exercise can reduce the severity of cognitive decline amongst at-risk older people.
For the full paper, go to the PLoS ONE website
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