Postural Tremor Reduction System Design for Parkinson’s Disease Patients

Abstract

Parkinson’s Disease is a neurodegenerative disease that affects fine movement control. It is generated by cellular death in the subtantia nigra which causes a decrement on the levels of dopamine in the body. Most treatments are based on the dosage of dopamine precursors or substitutes. These treatments alleviate the symptoms, such as the postural tremor, which is the most common in Parkinson’s disease. The downside to these treatments is, after approximately five years of usage, it turns ineffective, having to increment the dosage. It also has second-hand effects, such as vomit, loss of memory and dementia. Other treatments include movement therapy for bradykinesia and the use of orthosis for tremor suppression. The current orthosis has a constant opposition to the movement. This opposition generates fatigue and after time, muscular injury. To avoid muscular fatigue and reduce the tremor, an orthotic system with an adaptable friction coefficient was designed to diminish the tremor amplitude in upper limbs produced by Parkinson’s disease in the first and second stages. We developed a mathematical model to describe the arm’s biomechanical dynamics, simulated in MATLAB, and validated with a prototype and an oscillatory entrance. We applied a PI controller and tested different reduction systems in order to find a reduction method adequate and comfortable for a Parkinson’s Disease patient.