There's plenty not to love about being middle-aged. But by the time today's 40- and 50-somethings reach the age at which they might develop Alzheimer's or dementia, it's likely doctors will know more about their early signs and have drugs to treat them before symptoms show. This week scientists at Harvard University, in the US, published research on a group of retired people they call "super agers'' who have brains that resemble those of people a third of their age, which could provide clues on how to prevent declines in memory."In the next 10 years we're going to get more evidence about the things people can do to prevent Alzheimer's and dementia," said Craig Ritchie, professor of the psychiatry of ageing at the University of Edinburgh, who is leading the trial.So, what do we know?Forget Sudoku, learn a languageBrain stimulation, not brain training, is essential to prevent cognitive decline, said Ritchie. "So, if you've done crosswords your whole life, learning to play the piano at 65 is going to benefit your cognitive health more than if you keep doing things you've always done";Build your cognitive reserve"Someone with a high cognitive reserve would have a mix of high education, a complex occupation and a high level of social engagement in old age," said Carol Brayne, a professor at Cambridge University;Aspirin and the brainSome studies have suggested that long-term use of aspirin is associated with a reduced risk of Alzheimer's; andHealthy body, healthy brain"The processes that cause heart attacks and strokes are also associated with dementia," said Jane Armitage, of Oxford University. ..