| Summary: | Tremor is the most common movement disorder and a prevalent symptom in neurological conditions such as Parkinson's disease (PD). Given the limitations of medication, which often carries significant side effects and may not effectively treat tremor, and the limited availability of surgical treatments such as deep brain stimulation, there is a pressing clinical need for non-invasive therapeutic alternatives. This thesis investigates the potential of phase-locked peripheral electrical stimulation, delivered non-invasively to a nerve in the wrist, in modulating Parkinsonian rest tremor. Our initial investigations involved individuals with PD using a large, non-portable pilot system. The findings highlighted the high variability of tremor, characterised by distinct oscillation patterns within individuals. We discovered significant instantaneous changes in tremor severity, particularly when these distinct tremor modes were considered. Depending on the participant-specific stimulation phases, tremor could be significantly suppressed or amplified. Additionally, the variability in tremor patterns presented challenges in accurate phase tracking due to shifts in the axis of maximum tremor excursion and changes in tremor centre frequency. In response to these challenges, we developed a portable and adaptable version of the system, designed to account for these dynamic changes in tremor characteristics. The in-house built device, along with its on-board adaptable phase tracker, underwent rigorous bench testing for verification. Subsequently, the system was validated in a clinical setting with individuals with PD. Although the device's performance was validated and it proved to be a robust research tool, the tremor suppression achieved, while significant, was modest. This thesis demonstrates the potential of non-invasive phase-locked peripheral electrical stimulation in tremor management, particularly in PD. It underscores the need for adaptable and patient-specific treatment strategies and paves the way for future research in non-invasive tremor suppression techniques.
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