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How cats and dogs are helping doctors predict dementia in people with Parkinson’s
Security images inviting users to type words, or click on pictures, to prove they are ‘not a robot’ are undoubtedly frustrating for many.
But scientists have discovered that some people with Parkinson’s disease struggle more than most at the task, and it could point to important changes happening in the brain.
Around 165,000 people are living with Parkinson’s disease in Britain, and up to half will also develop dementia within 10 years of diagnosis. But currently doctors are unable to predict who is at most risk.
Now Dr Rimona Weil, of University College London, has developed a quick and simple test to determine which people with early-stage Parkinson’s are likely to develop dementia.
It involves distorted pictures of cats and dogs and works in a similar way to CAPTCHA images, the online security check using distorted text to tell humans and computers apart.
“Parkinson’s is the second most common neurodegenerative disorder after Alzheimer’s disease, but what isn’t widely known is half of people will go on to get dementia,” said Dr Weil.
“People are terrified about developing dementia so we think it is really important to be able to distinguish who is most at risk.
“A colleague told me that patients struggled to read CAPTCHA images and I started wondering whether if there was a point of distortion which the brain could no longer tolerate, which might suggest that dementia was more likely.
“We found that there was a point where they could no longer tell whether an animal was a car or a dog anymore. We think it might be to do with changes in the wiring of certain areas of the brain.”
Tests involving 20 people with Parkinson’s and 11 controls showed those who struggled to tell whether the image was that of a dog or a cat also did poorly on tests measuring overall cognitive performance. The Cats-and-Dogs test is quicker and better at spotting problems in visual processing that precedes dementia.
However Dr Weil said people should not be concerned if they struggled with the images.
“Not being able to see just one picture isn’t a problem, and our test looks at many images over time,” she added.
“We’re hoping that once we can tell who is likely to go on to develop dementia we can put them forward for trials of new drugs. In future, when drugs for dementia are available it will also help to spot early on the people who will benefit.”
The researchers have just launched a large, three year longitudinal study to see how well the Cats-and-Dogs test predicts cognitive decline over time, as measured by brain scanning and retinal imaging.
Anyone wanting to join the study should email a.costantini@ucl.ac.uk if you are outside of the London, and l.leyland@ucl.ac.uk if you live within the M25.
The study was published in the journal Movement Disorders.