The Objective Measurement of Sleep-Wake Disturbance in Parkinson's Disease

Abstract

Parkinson’s disease (PD) is an increasingly prevalent neurodegenerative disease affecting older adults. Motor symptoms, including tremor, rigidity and tremor were classically predominant. However, troublesome non-motor symptomatology are known to impair quality of life for patients with PD and there carers. Sleep-wake disturbances are gaining attention in PD encompassing disturbances of the circadian, homeostatic and ultradian sleep systems. These symptoms have been linked to the troublesome problems of cognitive deficits, mood disturbance and visual hallucinations. Mechanisms exploring the interaction of sleep-wake disturbance and other non-motor symptoms in PD are not well understood. Bidirectional causality between sleep-wake disturbance and concomitant symptoms in PD provide insights into common chemical and neural mechanisms which prior to the development of therapy, must be understood. Furthermore, sleep-wake disorders in PD at present provide a maker of early diagnosis for which future disease modifying treatment can be targeted. However objective and reliable measurement techniques are yet to be devised in this field. This thesis aims to utilise the objective measurement of sleep-wake disturbances across the circadian, homeostatic and ultradian sleep systems in PD through four empiric experiments to help inform our understanding of these critical symptoms. While the usefulness of self-report data is not doubted as a means of engaging the patient and hearing their voice they cannot serve the same identification and measurement uses of objective data. Given our ageing population, the need for diagnostic, predictive and sensitive monitoring biomarkers in Parkinson’s disease has never been greater. Objective, accurate and reliable measurement techniques, as demonstrated in this thesis, underpins further research in this field.