A digital pen with built-in sensors can diagnose signs of dementia and Parkinson’s disease more quickly and accurately than a doctor, research suggests.
The £160 pen can analyse every stroke, angle and hesitation of a patient who has been asked to perform a series of drawing tasks by measuring the position of the tip 80 times per second.
The process has been developed by scientists in the US, who have been working to digitise a 50-year-old process used by GPs and neurologists known as the “clock-drawing test”.
The test asks a patient to draw from memory a clockface with hands set to a specific time and then asks them to copy a pre-drawn clockface — known as the “control clock” — with hands set at the same time.
Doctors then judge the accuracy, neatness and completeness of the completed drawing by eye to assess whether the patient may be suffering from a memory impairment disorder such as Alzheimer’s or a motor skills disorder such as Parkinson’s.
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Those with Alzheimer’s tend to perform poorly when trying to draw a clock from memory, tending to draw larger, more elliptical clock faces, omitting numbers and forgetting the time they were asked to draw. Those with Parkinson’s tend to draw much smaller, narrower and scruffier clock faces with signs of having struggled to control their hand movements.
Researchers from MIT and other US universities said: “While there is a variety of well-regarded manual scoring systems, these often rely on the clinician’s subjective judgment of under- specified properties of the drawing.”
Rather than asking doctors to judge by eye whether there has been a “minor distortion” on the shape of the clock or whether the hour hand is “clearly shorter” than the minute hand, the Anoto Live Pen — available for $249 (£159) and commonly used to digitise sketches or signatures — can measure the exact length of the hands, the precise distortion of the clock face and the position of all the numbers.
It can also record “every stroke, pause or hesitation” from the patient, adding a new layer of analysis to the test.
Researchers used the pen in 2,600 tests over nine years and found that those with Alzheimer’s spent more time thinking about what they had to draw before putting pen to paper and also left a long gap between placing the numbers on the clock face and deciding where to place the hands.
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Those with Parkinson’s tended to take much longer over the process of drawing the clock and used a higher total number of strokes.
Cynthia Rudin, a professor at MIT, told MIT News: “We’ve improved the analysis so that it is automated and objective. With the right equipment, you can get results wherever you want, quickly and with higher accuracy.”
Eric Karran, a director at Alzheimer’s Research UK, said the clock-drawing test was only one in a series of methods used in diagnoses, but said: “Harnessing new technology to provide more accurate diagnoses is always welcome, although it will be important to test this device in a larger number of people and in multiple medical centres. Improving the accuracy and timeliness of a dementia diagnosis is crucial to help people receive the right support, access treatments and receive opportunities to take part in clinical research.”
Dementia UK warned against using the pen for self-diagnosis.