Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Engineering Science

Program

Biomedical Engineering

Supervisor

Patel, Rajni V.

2nd Supervisor

Jog, Mandar S.

Co-Supervisor

Abstract

Non-motor Parkinson’s Disease (PD) symptoms are substantial factors of PD arising throughout disease stages, yet their diagnosis and monitoring remain a challenge. Sensory abnormalities in PD occur across sensory systems and disease stages, contributing to disease-related impairments. However, the extent of symptoms is unknown, with inadequate monitoring and treatment options furthering disease management difficulties. The current work studies movement-independent visual perceptions of time, displacement and velocity in PD patients across disease stages using levodopa, deep brain stimulation (DBS), or no PD therapy. Perceptual tasks were conducted using a computer-generated graphical device designed with a focus on simplicity and flexibility. Perception of all tested visual modalities was impaired in PD (often extending to early PD stages), with negligible levodopa and DBS induced improvement. The observations help explain visuospatial, visual recognition and timing deficits occurring in PD while providing potential disease markers, and validates the graphical tool’s usefulness for disease diagnosis and monitoring.

Summary for Lay Audience

Parkinson’s disease (PD) is one of the most common movement disorders in Canada, affecting over 100, 000 Canadian residents, leading to an economic burden of over $120 million a year. Although the movement-related symptoms are the most commonly known, non-motor symptoms are also widely present in the disease throughout all stages, and are commonly reported to be more significant contributors to deficits in patient quality of life. The primary focus of treatment however is still directed at the motor symptoms, with available therapies and diagnostic procedures primarily targeting these motor symptoms. Furthermore, the extent of non-motor symptoms has yet to be discovered. Due to the disease symptoms presenting themselves differently on an individual basis, and numerous non-motor symptoms arising early in the disease (sometimes before motor symptoms) optimized patient treatment does not occur in many cases. Based on the above, this thesis aims to study select visual non-motor phenomena, to examine their potential dysfunction in PD, as well as their potential use for disease monitoring and diagnostic procedures. This thesis analyzes the visual perception of time, displacement and velocity in individuals with PD, the effect of common pharmaceutical (levodopa) and non-pharmaceutical (deep brain stimulation) therapies on these perceptions, and the use of a computer-generated graphical tool to analyze said perceptions. It was found that all of the studied perceptions were abnormal in PD, even at the early stages of the disease. Furthermore, the tested therapies did not appear to improve these perceptions, with levodopa potentially having a detrimental effect on temporal and velocity perceptions. The use of the graphical software was validated throughout the studies and presents itself as a potential disease monitoring and diagnostic tool that can easily be implemented in clinical and non-clinical settings to aid disease management. Furthermore, the findings regarding the studied perceptual dysfunction occurring independently of movement provides further insight into non-motor PD abnormalities, while helping to explain the phenomena of timing, spatial, and object recognition deficits occurring in PD.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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