Stroke is a leading cause of chronic disability and second leading cause of death globally. Vascular cognitive impairment (VCI) is one of the major sequelae of stroke and transient ischemic attack (TIA) with negative functional impact and elevated risk for institutionalization, dependency and death. Therefore, the overarching aim of this thesis is to characterize neuropsychological patterns of post-stroke VCI and improve outcome after stroke by establishing optimal VCI screening, prognosticating cognitive and functional outcome and investigating the efficacy of the external carotid-internal carotid (EC-IC) bypass revascularization neurosurgical intervention. The findings include, firstly, the widely used cognitive screening instruments, both the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE), were equivalent and moderately sensitive in detecting VCI 3–6 months after stroke. However, the addition of a visuomotor processing speed measure can improve the accuracy of VCI screening. Secondly, the neurocognitive status measured by the MoCA and the MMSE at the subacute stroke phase (i.e., within two weeks after vascular events) could predict both cognitive outcome and functional outcome at 3–6 months later. Thirdly, the cognitive performance of ischemic stroke/TIA patients was worse than stroke-free non-demented controls, globally as well as in all individual domains except the episodic verbal memory, which was relatively spared. This study also supports the impact of lesion location and severity on the pattern of cognitive deficits. Finally, the EC-IC bypass surgery in carefully selected severe intracranial steno-occlusive disease patients could result in significant improvement in cerebral hemodynamics and performance in verbal memory and executive function. These findings provide evidence for routine VCI screening, customized rehabilitation and discharge planning at the subacute stroke phase for better prognosis in patients at a higher risk for significant VCI and/or functional decline. It also provides a well-characterized neuropsychological profile to aid differential diagnoses in post-stroke VCI and effective cognitive end-point measures in therapeutic intervention, as well as the preliminary evidence of EC-IC revascularization as a promising intervention for patients with severe steno-occlusive disease.
I was inspired by the great team of enthusiastic researchers at CHeBA who are devoted to academic research and working hard to make a difference in policy and practice through scientific evidence. My academic skills and research knowledge has developed substantially from the daily exchange with various researchers at CHeBA as they have highly specialised domain knowledge.