In a phenomenon called the Flynn effect the IQ of the population tends to go down over time. This is as true of older people as it is of younger ones and could mean that it is more difficult to predict which people will go on to develop dementia using standardized tests. Simona Sacuiu, a Ph.D. student at the University of Gothenburg compared the test results of 70-year-olds in the early 1970s with those of 70-year-olds in 2000; none of those tested at either period had dementia. The results of people in 2000 were much higher suggesting that these tests can no longer be used to predict accurately which people will develop dementia. Five years after the test 5% of the participants had developed dementia. Those with memory problems showed an increased risk of developing dementia although not everyone with memory problems went on to develop the condition, further confusing the picture. 300 85-year-olds were also tested, 17% of whom developed dementia three years later. These participants were tested on their ability to draw geometric shapes and find words and only people who found difficulties with these tasks as well as having memory problems, were at an increased risk of developing dementia.
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