Neurocognitive predictors of post-stroke cognitive trajectory

The current thesis examined cognitive trajectories following stroke, and tested potential predictors of cognitive outcome, and trajectories. It used data from two existing databases: the Birmingham Cognitive Screen Study (BUCS) collected in the UK, and the C-BCoS collected in China, and newly collected data as part of the HiPPS-CI study (The role of Hippocampus Pathology in Post-Stroke-Cognitive Impairment). Chapter two aimed to answer the question; does the proportional recovery rule exist in cognition, as it does with motor recovery? We found that 80% of patients showed 40- 50% proportional recovery of cognition at nine months post-stroke. This was evident across and within cognitive domains. Recovery was not limited to the first three months following stroke. We further identified two other recovery trajectories, where around 10% of patients showed an accelerated recovery, while around 10% showed decelerated recovery and even decline. We then investigated the predictive value of years of education on post-stroke cognitive outcomes, and recovery rate (Chapter three). We found that education improved cognitive outcomes following stroke, and accelerated recovery in the first year following stroke beyond age. Finally, we explored the predictive value of hippocampal pathology, and the impact of hippocampal pathology on post-stroke cognition. We found that beyond stroke and age, hippocampal pathology predicted cognition within three months post-stroke. This was evident in grey matter volume, mean diffusivity, creatine, choline and N-acetylaspartate. Hippocampus pathology (specifically grey matter volume) interacted with education, age, vascular risk, cortical atrophy and small vessel disease. These factors also predicted cognition. It is concluded that post-stroke cognitive outcomes are affected by pre-stroke clinical, and socio-demographic factors, where education ameliorates the impact of stroke on cognition potentially by preserving the hippocampus, while neurovascular health potentially aggravates the cognitive impairments