Tremor Reduction at the Palm of a Parkinson's Patient Using Dynamic Vibration Absorber

Area of Science:

• Biomechanics
• Neurology
• Mechanical Engineering

Background:

• Parkinson's disease (PD) is characterized by severe tremors resulting from central oscillator abnormalities.
• Current medications for involuntary muscle contractions pose significant risks to PD patients.
• Mechanical vibration absorbers present a promising alternative treatment for managing PD-related tremors.

Purpose of the Study:

• To develop a dynamic model of the human hand to characterize the biodynamic response in PD patients.
• To design an effective tuned vibration absorber capable of mitigating pathological tremors.

Main Methods:

• The human hand was modeled as a three-degrees-of-freedom (DOF) system simulating proximal joint flexion.
• Resting tremor was modeled as dual harmonic excitation from shoulder and elbow muscle activation at resonance.
• A single dynamic vibration absorber (DVA) and a dual DVA were designed and their performance evaluated using complex transfer functions.

Main Results:

• The dual DVA demonstrated superior efficiency in tremor reduction compared to the single DVA.
• The dual DVA reduced tremor amplitude by 98.3%-99.5% at the shoulder, 97.0%-97.3% at the elbow, and 97.4%-97.5% at the wrist.
• Absorbers were constructed using stainless steel alloy cantilevered beams with attached copper masses.

Conclusions:

• A dual dynamic vibration absorber is highly effective in suppressing pathological tremors in Parkinson's patients.
• The developed dynamic model accurately represents the biodynamic response of the PD hand.
• This mechanical approach offers a safe and efficient non-pharmacological treatment strategy for Parkinson's tremors.