单项选择题

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(n) (1) rise in the popularity of brain-training games. But how (2) really is a daily dose of cryptic crossword
Robert Wilson, a neuropsychologist at Rush University in Chicago, and his colleagues decided to (3) out, (4) following a group of people without dementia. Participants were asked to (5) how frequently they engaged in cognitively (6) activities. The researchers were looking for such things as reading newspapers, books and magazines, (7) challenging games like chess, listening to the radio and watching television, and (8) museums.
The good news, as they report in Neurology, is that (9) activity of this sort seems to slow the rate of (10) decline in those without cognitive (11) . The bad news is that in those who do then develop Alzheimer’s disease it is associated with a more rapid (12) decline.
What seems to be happening is that cognitive stimulation helps (13) the effect of the neurodegenerative lesions associated with dementia. It does not, (14) , make them go away. They continue to (15) , so that when the disease does eventually take (16) there are more of them around than there otherwise would be, which results in a more (17) cognitive fall off. That is not a message of despair, (18) , because the length of time someone suffers from dementia is thus (19) and their healthy life prolonged. So the message is, (20) on with the crosswords.

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