Longevity

If you want to live a long life - count me in - being smart might help you dodge senile dementia.

* 17 December 2005 * Lisa Melton

RICHARD WETHERILL was intolerably good at chess. Hardly surprising, for the retired university lecturer could think a mind-boggling eight moves ahead. But in recent months, his razor-sharp mind had started to dull. When he found he could no longer think five moves ahead, he was sure something was seriously wrong and arranged to meet neurologist Nick Fox at University College London's Institute of Neurology. Though his wife dismissed his complaints, Wetherill was adamant that he needed help. Yet Fox's battery of tests revealed nothing amiss: his patient sailed through every test designed to spot early dementia. Under a brain imager, his brain looked normal.

Two years later, in 2003, Wetherill died suddenly. Imagine Fox's amazement when the autopsy revealed a brain riddled with plaques and tangles, the hallmark of Alzheimer's disease. The anatomical evidence indicated advanced disease, with a level of physical damage that would have reduced most people to a state of total confusion. Yet for Wetherill the only impact was that he could no longer play chess to high standards. What on earth was he doing differently? What was cushioning the blow?

Wetherill's experience is a perfect example of a phenomenon that has long puzzled scientists: people who lead more intellectually stimulating lives, who are more intelligent, better educated and have high-status occupations, are somehow protected from the mental decline that comes with age. And not just age, but other insults too, from head injuries and alcohol intoxication to stroke, HIV, Alzheimer's and Parkinson's disease.