Session: 07-05-01: Dynamics and Control of Biomechanical Systems

Paper Number: 168180

Nonlinear Hand Tremor Suppression for Parkinson's Disease 

Parkinson's Disease, a progressive neurodegenerative disorder that significantly impairs the central nervous system, affecting over 10 million people worldwide.  Parkinson’s Disease is progressive, and so much of the active related research is in slowing the progress.  This study targets hand tremors.  Hand tremors, a motor symptom affecting the physio-mechanical communications, affect up to 75% of Parkinson's patients and substantially compromise functional independence.  Even more common, Essential Tremor impacts an another estimated 40 million people globally, with similar manifestations.  These involuntary oscillatory movements interfere with essential activities of daily living including eating, drinking, writing, and personal hygiene, with quantitative assessments demonstrating a 76% reduction in fine motor task performance compared to age-matched control groups, which make significant contributions to social isolation and psychological distress. While current treatments exist, they typically involve either prohibitive costs or invasive procedures such as deep brain stimulation, creating significant barriers to treatment access for millions of affected individuals. This research presents the development of a novel, low-cost wearable device designed to mitigate hand tremors in Parkinson's patients.  Critical to the design process is the consideration that tremors can manifest in a variety of different hand motions, and the rate of these tremors varies with patient stress, diet, position, and over time.  Correspondingly, the wearable device presented here is adjustable to track individual tremors as they happen.  Additionally, the device should be comfortable and affordable.  While human subject testing has been performed, for the purposes of consistent and verifiable results, a mechanical hand apparatus is introduced.  Properties of this mechanical device can be adjusted to model the different hand tremor motions and to represent different hand biometrics.  Iterative design phases refined the device architecture to optimize tremor suppression when tested on a physical mechanical hand apparatus.  Stimulus and response data is collected for evaluating the effectiveness of the apparatus. The design proposed here is shown to be adjustable to cover double the effective frequency range of the most recent study.  This comes with a reduction in weight of 44% and a reduction in volume of 54%.  These results are achieved while maintaining criteria for size, comfort, and affordability.  Notably, exploration in the incorporation of nonlinear dynamic elements has yielded substantial improvements in tremor projected reduction efficacy in simulation runs.  These nonlinearities have been designed and prototyped for the physical apparatus.  In this ongoing effort, a variable nonlinear stiffness mechanism has been built and assessed, informing simulation studies. 

Presenting Author: Timothy Doughty University of Portland

Presenting Author Biography: Tim received his doctorate from Purdue University and is currently Professor and Chair of the Mechanical Engineering for the Donald P. Shiley School of Engineering at the University of Portland. He has served as a Dundon Berchtold Fellow of Ethics, a Faculty Scholar for the Lawrence Livermore National Labs, and as an associate editor for ASME's Dynamic Systems and Controls Division for conference proceedings. Tim’s research is in nonlinear dynamics, assistive technology, nondestructive health monitoring, character and ethics.

Authors:

Timothy Doughty University of Portland
Owen Gent University of Portland
Adin Sokol University of Portland