Quantitative Evaluation of Spiral Drawing by Patients with Movement Disorder based on Polar Coordinate System with Varied Origin

In this study, quantitative evaluation of spiral drawing by patients with movement disorder was investigated in order to extract characteristics of hand movement disabilities. The hand movement of circular spiral drawing was recorded by a digitized tablet. A method of polar coordinate system with varied origin was proposed for evaluation. A set of characteristic parameters were also defined and calculated. Compare with fixed origin, the variation of radius, origin and degree can be evaluated quantitatively. The proposed method of polar coordinate with varied origin is effective to help clinicians in diagnosing the diseases and inspecting the effectiveness of operation and treatment.