Handwriting assessment can be used for early detection of Parkinson’s disease

Recent studies have found distinct differences between the handwriting of patients with Parkinson’s disease and that of healthy people.

hand writing 370 (photo credit: REUTERS)
hand writing 370
(photo credit: REUTERS)
Parkinson’s disease, a degeneration of the central nervous system whose most prominent clinical symptoms are shaking, slowness of movement and rigidity, can be detected early through a noninvasive handwriting- analysis technique developed at the University of Haifa and Rambam Medical Center.
Until now, the primary tool for diagnosing Parkinson’s was an examination by an expert physician, who could usually identify clinical symptoms only after the disease had progressed considerably.
Physicians often conduct a test called SPECT, which uses radioactive material to image the brain. This technique is no more effective than an assessment by a medical specialist, and it exposes the patient to unnecessary radiation.
Recent studies, however, have found distinct differences between the handwriting of patients with Parkinson’s disease and that of healthy people.
“Identifying the handwriting changes could lead to an early diagnosis of the illness and neurological intervention at a critical moment,” explained Prof. Sara Rosenblum of the university’s occupational therapy department, who initiated the study.
Most studies until now have focused on motor skills (such as the drawing of spirals) while ignoring cognitive abilities, such as signing a check, copying addresses and so on.
According to Rosenblum, Parkinson’s patients report an awareness of change in their cognitive abilities before detecting a deterioration in motor skills. Therefore, testing cognitive impairment, as was done in this study, might hint at the presence of the disease and offer a way to diagnose it earlier.
The study was conducted in cooperation with Dr. Ilana Schlesinger, head of Rambam’s Center for Movement Disorders and Parkinson’s disease, and occupational therapists.
They asked subjects to write their names and gave them addresses to copy – two routine tasks that require cognitive capability. Forty adult participants with at least 12 years of schooling – half healthy and half known to be in the early stages of Parkinson’s disease, before a deterioration of motor skills was apparent – participated.
The writing was done on a regular piece of paper that was placed on an electronic tablet, using a special pen with pressure- sensitive sensors that were activated upon hitting the writing surface. A computerized analysis of the results compared a number of parameters: writing form (length, width and height of the letters), time required and pressure exerted.
Analysis of the results showed significant differences between the patients with Parkinson’s and the healthy group. The diagnosis was correct (at 97.5 percent accuracy) for all subjects except one.
Those afflicted by Parkinson’s wrote smaller letters, exerted less pressure on the writing surface and took more time.
According to Rosenblum, a particularly noticeable difference was the length of time the pen was in the air between the writing of each letter and each word.
“This finding is particularly important because, while the patient holds the pen in the air, his mind is planning his next action in the writing process, and the need for more time reflects the subject’s reduced cognitive ability.
Changes in handwriting can occur years before a clinical diagnosis and therefore can be an early signal of the approaching disease,” Rosenblum said.
According to Schlesinger, validating these findings in a broader study would allow this method to be used for a preliminary diagnosis in a safe, noninvasive fashion.
“This study is a breakthrough toward an objective diagnosis of the disease,” she said. “Publication of the study in the journal of the European Neurological Society aroused great interest at the International Congress of Parkinson’s Disease and Movement held last week in Sydney, Australia.”
The researchers note that this diagnostic method has the added benefit of reducing the load on the health system because the test can be performed by a professional other than a doctor. After the results are in, patients can be referred to a doctor for further treatment and testing if necessary.
The researchers are using this method in a new experiment, in which they use handwriting analysis to evaluate the degree of Parkinson’s patients’ improved functioning after the implanting of brain pacemakers.