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Ïã¸ÛÁùºÏ²ÊÖÐÌØÍø Institute of Neurology researchers have developed a quick and simple test to predict which people with early-stage Parkinson’s disease are likely to develop dementia.

Lead researcher Dr Rimona Weil (Dementia Research Centre and Movement Disorders Centre, Ïã¸ÛÁùºÏ²ÊÖÐÌØÍø Institute of Neurology) says that dementia is aÌýseriousÌýconcern among people with Parkinson’s, as the diseaseÌýcanÌýoften develops into dementia, but early warning markers are currently lacking.

The research team developed their idea for the test after noticing that many people with Parkinson’sÌýsay they haveÌýtrouble reading CAPTCHA images, an online security check using distorted text to tell humans and computersÌýapart.

They derived a test tasking participantsÌýto identify whether a distorted image depictsÌýa cat or a dog.ÌýIn their study of 20 people with Parkinson’s and 11 controls, those who struggled with the task also did poorly on moreÌýin-depthÌýtestsÌýof overall cognitive performance, andÌýhadÌýhigherÌýscores on a risk measure,ÌýpreviouslyÌýdeveloped by one of the IoN researchers, that uses cross-sectional data.

The Cats-and-Dogs testÌýwas a more sensitive measure than existing visuospatial tests, as well as a control task that made cat and dog images harder to see by adding visual noise.ÌýThe researchers say the Cats-and-Dogs test is quicker, more sensitive and more specific than other methods that test forÌýtheÌýdecline in visual processing that precedesÌýdementia.

The researchers have just launched a large, longitudinal study to see how well the Cats-and-Dogs test predicts decline over time, as measured by brain scanning and retinal imaging.ÌýThey also have an online version of the test for another study that will help them compare the measure to other genetic factors.

The study was supported by the National Hospital for Neurosurgery and Neurology, Wellcome, the European Research Council, theÌýEconomic and Social Research Council, theÌýNational Institute for Health Research, the Academy of Medical Sciences, theÌýEngineering and Physical Sciences Research Council, Parkinson’s UKÌýand Alzheimer’s Research UK.

The study was published in the journal Movement Disorders.

Further information

To take part in the longitudinal study please contact

• In London: Dr Louise LeylandÌýl.leyland@ucl.ac.uk
• Outside London: Alyssa CostantiniÌýa.costantini@ucl.ac.uk

• Weil et al. Available online 4 October 2017 DOI: 10.1002/mds.27176