AS THE baby-boomer generation contemplates the prospect of the Zimmer frame there has never been more interest in delaying the process of ageing. One consequence has been a dramatic rise in the popularity of brain-training games. But how effective really is a daily dose of cryptic crossword?

Robert Wilson, a neuropsychologist at Rush University in Chicago, and his colleagues decided to find out, by following a group of people without dementia. Participants were asked to rate how frequently they engaged in cognitively stimulating activities. The researchers were looking for such things as reading newspapers, books and magazines, playing challenging games like chess, listening to the radio and watching television, and visiting museums.

The good news, as they report in Neurology, is that frequent activity of this sort seems to slow the rate of mental decline in those without cognitive impairment. The bad news is that in those who do then develop Alzheimer’s disease it is associated with a more rapid subsequent decline.

What seems to be happening is that cognitive stimulation helps overcome the effect of the neurodegenerative lesions associated with dementia. It does not, however, make them go away. They continue to accumulate, so that when the disease does eventually take hold there are more of them around than there otherwise would be, which results in a more rapid cognitive fall off. That is not a message of despair, though, because the length of time someone suffers from dementia is thus reduced and their healthy life prolonged. So the message is, carry on with the crosswords.