Since treatment options for Parkinson’s disease are effective only when the diagnosis is made early, a new software being trialled by a group of Australian researchers could be a harbinger of better clinical trials. A test that involves drawing a spiral on a sheet of paper could be used to diagnose early Parkinson’s. The software in question measures writing speed and pen pressure on the page. Both are useful for detecting the disease, which causes shaking and muscle rigidity.
Parkinson’s is associated with movement disorder symptoms, such as tremor, rigidity, slowness of movement (bradykinesia), and postural instability. The manifestation of bradykinesia and rigidity is often in the early stages of the disease. These have a noticeable effect on the handwriting and sketching abilities of patients, and micrographia (an acquired disorder that features abnormally small, cramped handwriting or the progression to progressively smaller handwriting) has been used for early-stage diagnosis of Parkinson’s. While handwriting of a person is influenced by a number of factors such as language proficiency and education, sketching of a shape such as the spiral has been found to be non-invasive and independent measure.
The association of handwriting and sketching of the spiral has been established in Parkinson’s in early stages. However, one shortcoming in the use of handwriting or sketching is the need for an expert to interpret the sketches, especially in the early stages of the disease. With the availability of digital devices that are suitable for recording hand-sketching, there is the potential for machine based assessment of writing and sketching. These devices are also suitable for obtaining the dynamic features of handwriting, which are suitable for real-time and reliable analysis. These features can be obtained automatically allowing rapid on-line assessment of patients and developed for applications such as biometrics and indicative markers for Parkinson’s.
The Melbourne team said the test could be used by general practitioners to screen their patients after middle age and to monitor the effect of treatments. The study, published in Frontiers of Neurology, involved 55 people – 27 had Parkinson’s and 28 did not. Speed of writing and pen pressure while sketching are lower among Parkinson’s patients, particularly those with a severe form of the disease. In the trial, a tablet computer with special software took measurements during the drawing test and was able to distinguish those with the disease, and how severe it was. The aim was to develop an affordable and automated electronic system for early-stage diagnosis of Parkinson’s, which could be easily used by a community doctor or nursing staff.
The system combines pen speed and pressure into one measurement, which can be used to tell how severe the disease is. David Dexter, deputy research director at Parkinson’s UK, said current tests for the disease were not able to accurately measure how advanced someone’s condition was. This can impact on the ability to select the right people for clinical research, which is essential to develop new and better treatments for Parkinson’s. The new test could provide a more accurate assessment by measuring a wider range of features that may be affected by Parkinson’s, such as co-ordination, pressure, speed and cognitive function.