Graphical tasks to aid in diagnosing and monitoring Parkinson's disease

Parkinson’s disease is a neurodegenerative disorder that is often characterized by motor symptoms. The four cardinal motor symptoms are bradykinesia (slow movement), resting tremor (trembling of a body part in rest), rigidity (muscular stiffness), and balance problems. In addition, a reduction in handwriting size (micrographia) is often seen. Correct diagnosis of Parkinson’s disease is essential for optimal treatment and to improve a patient’s quality of life. Currently, the Unified Parkinson’s Disease Rating Scale (UPDRS) is the most widely used method to assess motor symptoms. This assessment depends on the experience and interpretation of the physician. Diagnostic accuracy improves with increasing clinical experience. Unfortunately, patients do not always have timely access to a movement disorder specialist and other health care workers could easily miss mild symptoms of Parkinson’s disease. Therefore a method that provides objective measures of the motor symptoms of Parkinson’s disease could be useful. In this thesis a newly developed system is evaluated for this purpose. The system consists of a sensor-pen and digital tablet, and records graphical tasks such as handwriting and drawing. This thesis shows that the new system provides objective measures to assess bradykinesia, micrographia and tremor simultaneously. Differences in performance on the tasks were found between Parkinson patients and healthy controls and patients with other tremor disorders. Additionally, an effect of medication was seen in Parkinson patients. This newly developed system is portable, non-invasive and could be easily used at home without an examiner and therefore offers great opportunities for future clinical applications.