Sleep disruption and cognitive dysfunction in Parkinson’s disease: does sleep disturbance exacerbate cognitive symptoms?

This thesis explores the relationship between disrupted sleep and cognitive impairment in Parkinson's disease (PD). I posit that while cognitive dysfunction and poor sleep may result directly from the pathology of PD, sleep disturbance may additionally exacerbate cognitive symptoms .The findings presented 1n this thesis, however, suggest that in PD, conventionally defined 'good' sleep may signal early cognitive decline. This novel work that reports an association between better sleep and poorer cognition 1n older-onset and unselected PD (but not young-onset PD or healthy controls) provides a compelling rationale for systematic, longitudinal study of sleep throughout the disease course.