The psychological and cognitive impact of cerebrovascular disease

Patients who experience a Transient Ischaemic Attack (TIA) or a stroke are at risk of subsequent psychological and cognitive disorders but there is limited research into the impact of transient or minor events. Psychological disorders include depression, anxiety disorders and post-traumatic stress disorder with their risk factors and prevalence rates after a TIA poorly described. Furthermore, whilst depression and anxiety after a major stroke is associated with increased risk of recurrent stroke and all-cause mortality it is not clear if the same can be said after a minor stroke or a TIA. Cognitive disorders after a stroke are a heterogenous condition including fixed or progressive cognitive impairment due to a stroke lesion, cognitive impairment accelerated by a stroke and cognitive impairment secondary to the coexistent pathology that also led to the stroke. However, the prevalence rates and associated factors for pre-stroke and post-stroke dementia have not been updated to reflect the impact of methodological factors on studies or the more recent improvements in stroke care. Recently, there has been a move to telephone cognitive assessments, particularly in research studies, and as such there is a need for accurate description of their potential limitations. Overall, the aims of my thesis are to describe the prevalence and risk-factors for anxiety and depression disorders after a TIA or minor stroke and the prevalence and associated factors for pre-stroke and post-stroke dementia. Additionally, I aim to describe the potential limitations of telephone cognitive assessments. I have collected and analysed data from the Oxford Vascular Study (OxVasc) which is an ongoing prospective, population-based incidence study of acute vascular disease in Oxfordshire, UK. The study population comprises approximately 92,729 individuals registered with eight general practices and uses multiple overlapping “hot” and “cold” methods to identify all relevant patients. Additionally, I collated and analysed data from the Treatment in Morning versus Evening (TIME) study which is a prospective, randomised open-label study comparing morning dosing of usual antihypertensive medication with evening dosing with a cognitive function sub-study (TIME-COG) of simple tests of cognition, administered via telephone, in participants aged 70 years or older. There are several clinically relevant findings in this thesis which improve understanding of the psychological and cognitive consequences of a TIA or stroke. First, I have described the prevalence rate and associated factors for post-TIA anxiety and depression disorders. Second, I have described the prognosis of post-TIA anxiety and depression disorders. Third, I have described the prevalence and associated factors for pre-stroke dementia with particular attention to the impact of methodological factors. Forth, I have described the prevalence and associated factors for post-stroke dementia with particular attention to the impact of patient selection. Finally, I have described the potential impediments to telephone cognitive assessments with particular attention to the impact of time-of-day and change in season.