Early stage Parkinson’s disease (PD) shares certain symptoms with essential tremor (ET), which makes it difficult to differentiate between the two. We analyzed cyclical body bends to find kinematic parameters that are capable of differentiating among PD, ET and normal control (NC) subjects. A linear discriminant analysis of the joint angles showed a reliable distinction between NC and the two groups of patients, while differentiating reasonably well between PD and ET. PD patients showed difficulty performing hip segment rotation around the vertical axis, whereas ET patients demonstrated enlarged torso sway in the frontal plane. These findings suggest that kinematic parameters of body movement in the standing position are sensitive enough to serve as subclinical marks in the early diagnosis of PD and ET.
Kurgansky, Frolov, and Ioffe are with the Mathematical Neurobiology of Learning Lab, Institution of Russian Academy of Sciences Institute of Higher Nervous Activity and Neurophysiology RAS, Moscow, Russia. Karabanov and Chernikova are with the Scientific Research Institute of Neurology of the Russian Academy of Medical Sciences, Moscow, Russia.