Intelligence tests offer insight into ageing brain
Sixty-six years ago today, more than 70,000 10 and 11-year-old children across Scotland took an intelligence test.
The results were painstakingly recorded and stowed away in a basement.
And there they stayed - largely forgotten - for the next five decades.
But now they have formed the foundation of a remarkable research project which is producing valuable insights into what lies behind cognitive decline - or ageing of the brain.
Every three years, Ina Wallace is put through a range of cognitive checks by researchers at Edinburgh University.
The tests include memory, mental speed, vocabulary and verbal abilities, planning and organisation.
She also re-takes an intelligence test she first encountered when she was a girl.
"I was at Musselburgh school and we went into the main hall and there were long lines of desks," she said.
"I was very worried because you had to write your name. I was very concerned because the line wasn't long enough. So I do remember it very vividly."
For Prof Ian Deary, the discovery of the records years later - piled high on shelves in an Edinburgh basement - presented a great opportunity.
They provide a unique record which now underpins his team's research into the ageing brain - the Disconnected Mind project.
They managed to make contact with more than 1,000 people from the Lothian area who took the test all those years ago, and agreed to a new round of questionnaires, brain scans, blood tests, and physical and mental checks.
"We have baseline cognitive function from when people were healthy in early youth," he said.
"It means we can estimate each individual's change in cognitive function across the life-course from childhood to old age, and then study them within old age."
He says another great strength of this data is that the people in the study are all the same age.
"It means we can study people of the same chronological age who are at a different biological age because some people have aged better than others."
The researchers are tracking these changes, and examining in detail what lies behind them - including social background, education, lifestyle, health, and genes.
"Load your Dice"
Already there have been important findings indicating - at a population level - that environmental factors outweigh the impact of genetics in ageing of the brain.
"It's not just about doing one thing or taking one thing and everything will be all right," said Prof Deary.
"It's a matter of choices of different things and playing the numbers. So if you know that if one thing is better to do than another, you're probably better to load your dice in the direction of things that look sensible."
So with cigarettes they found those with lower test scores at 11 were more likely to take up smoking, which then harmed cognition scores later on.
More education did appear to boost mental ability in later life, at least for high-level skills such as reasoning. But it did not help for simple mental tasks such as speed of reaction.
There was little evidence that intellectual activities such as watching Shakespeare or playing Sudoku did anything to boost the brain.
Healthy brain scans
But physical activity was beneficial for memory and reasoning skills - and it showed up in healthier brain scans.
The cohort in the study have nearly all completed their third series of checks since they were contacted by researchers. Ina Wallace said she "peaked" at 70, but she still beats her score from 1947.
"I definitely feel I have slowed down a bit. I was pleasantly surprised at the results of the last one. I'm higher than I was when I was 11. A wee bit better definitely. Not a lot, but a little!"
Alison Pattie, who is part of the research team, has been struck by the ability of some she's assessed to think back to that day in 1947.
"Most people don't actually remember sitting their test but there are a good few who do remember it. There are a few people who actually remember specific questions. It's pretty amazing I would say."
The "biggest fear"
A lot of the funding for this project has come from Age UK.
The charity's head of research, Prof James Goodwin says cognitive decline is the biggest fear of older people, and information emerging from the disconnected mind project will help many who may be worried to age well.
"If we can provide those answers it will mean that information, advice, evidence to older people themselves, to people in middle age who want to age successfully, and also to professional people will be available and will have huge tangible benefits."