Mechanical Modeling and Design for Reduction of Parkinsonian Hand Tremor

Most of the active research in reducing Parkinsonian tremor involves invasive surgeries or medical treatment. In this paper hand tremors associated with Parkinson’s Disease (PD) are studied and passive vibration control methods are developed and tested. Patients with PD are surveyed regarding difficulties with hand tremor during the act of eating. The result leads to design criteria for an enhanced eating utensil and the establishment of meaningful testing methods for measuring hand tremor. Tremor data collected from several PD patients provides insight into the nature of the motion and allows for the development of test fixture and prototypes. This experimental data is coupled with linear model identification testing for the free response of a “healthy” hand undergoing the same motions. The resulting differential equation model, where the system input is realized as actuation through the biomechanics of the forearm and wrist, is used in the design of an eating utensil for vibration reduction. With self-excitation and the existence of harmonics, the tremor data is also used to develop a nonlinear differential equation model, where the complete neurological/mechanical system is realized with an equivalent mechanical system. This nonlinear model is shown to mimic the tremor data and is used to enhance the development of the vibration absorber. A prototype of the vibration absorber is built, validated on the test fixture, and tremor reduction data is collected again with PD patients.