• Up to 10% of women pass tests for cognitive impairment when they should not
• This is important because cognitive impairment frequently leads to dementia 
• If not picked up early, medications and lifestyle changes may not work as well 

By VICTORIA ALLEN SCIENCE CORRESPONDENT FOR THE DAILY MAIL

Memory problems may be missed in women because they perform better in certain tests than men.

A study has found as many as 10 per cent of women pass tests for cognitive impairment when they should not.

This is important because cognitive impairment frequently leads to dementia. If it is not picked up early, medications and lifestyle changes may not work as well.

Women tend to do better in memory tests because they are better than men at remembering lists of words they have heard read aloud.

A study of almost 1,000 people given cognitive tests found just over a quarter of women had mild cognitive impairment.

But when the test results were adjusted for females’ better verbal memory, it emerged more than a third may in fact have memory problems.

This was backed up by brain scans showing the additional women were more likely to have clumps of protein which have been linked to memory problems and dementia.

Dr Erin Sundermann, first author of the study from the University of California, San Diego, said: ‘If these results are confirmed, they have vital implications.

‘If women are inaccurately identified as having no problems with memory and thinking skills, when they actually have mild cognitive impairment, then treatments are not being started and they and their families are not planning ahead for their care or their financial or legal situations.

‘And for men who are inaccurately diagnosed with mild cognitive impairment, they can be exposed to unneeded medications along with undue stress for them and their families.’

The test looked at by the US researchers, which read older people a list of 15 words and asked them to remember as many as possible, is not the standard test in the UK.

But a similar verbal memory test is one of those recommended for Alzheimer’s disease by health watchdog NICE.

The study looked at 985 people asked to recall a word list straight away, after 30 minutes and after hearing a separate list designed to distract them.

As expected, women did better than men, as they are thought to process language well on both sides of the brain, while men rely more on the brain’s left side, putting them at a disadvantage.

When the test results were adjusted to reflect women’s better performance, those found to meet the cut-off for cognitive impairment rose from 120 women, or 26 per cent of participants, to 165 women, or 36 per cent.

The number of men judged to be cognitively impaired fell from 239 to 184, or from 45 per cent of men to 35 per cent of them.

The brain scans showed that women who appeared wrongly to have passed cognitive tests were more likely to have clumps of tau and amyloid in their brain – proteins which are linked to dementia.

Men thought to have cognitive impairment, before the new analysis found they did not, had brains similar to those who passed the test the first time round.

Responding to the research, published in the journal Neurology, Dr James Connell, Research Manager at Alzheimer’s Research UK, said: ‘In the UK, doctors test people’s verbal memory as part of a wider assessment to help diagnose problems with memory and thinking.

‘Findings like this could improve diagnosis methods, making it easier to spot people who are at risk of developing diseases like Alzheimer’s.’

The NICE guidance on dementia states that dementia should not be ruled out solely because someone has a normal score on a cognitive test.