How a simple drawing test can detect Parkinson's disease

The program works by analysing how long it takes volunteers to draw a spiral on a tablet computer. Photo / 123RF

Drawing a simple spiral can determine whether or not a person has Parkinson's disease far enough in advance to stave off brain damage, an Australian study has found.

The new diagnostic method is the first to be able to spot the disease early enough to allow preventive treatment.

The program works by analysing how long it takes volunteers to draw a spiral on a tablet computer, how much pressure they exerted and the characteristics of the lines.

Currently, Parkinson's disease is often diagnosed when a person is already suffering from tremors and rigidity, and by that stage many of their dopamine-producing brain cells have died.

The earlier doctors are able to administer treatment, the larger the number of neurons they can save, significantly slowing the progress of the disease.

Scientists already knew that symptoms that appear early in the disease can interfere with a person's ability to write or sketch.

A spiral is considered a sound test because, unlike writing words, the quality is less likely to be influenced by a patient's education.

However, at present the method requires highly trained experts to interpret the sketches, meaning the tool has not enjoyed widespread use.

By contrast, the new drawing tablet program is designed to be easy to use, meaning it can be operated by any family doctor.

"Pushing back the point at which treatment can start is critical because we know that by the time someone starts to experience tremors or rigidity, it may be too late," said Prof Dinesh Kuman, from RMIT University in Melbourne, who led the study.

People with Parkinson's tend to move their pens more slowly when sketching and they also apply less pressure to the page.

Published in the journal Frontiers in Neurology, the study claims the new system can automatically detect whether a user has Parkinson's or not with 93 per cent accuracy.

Twenty-seven people in their sixties and seventies with varying severities of Parkinson's were tested on the system, as well as 28 of comparable age who were not Parkinson's sufferers.

"Our aim was to develop an affordable and automated electronic system for early-stage diagnosis of Parkinson's disease, which could be used easily by a community doctor or nursing staff," said Poonam Zham, another of the researchers.

He added that the device could be used as part of routine screening for the disease which could take place every few years past middle age.

The data from the Australian study will need to be used on significantly larger numbers of patients before it is commonly introduced to GP surgeries.