Domain-specific trends in cognitive impairment after acute ischaemic stroke

Little is known about the pattern of subacute cognitive domain impairments after ischaemic stroke, nor the temporal evolution of such impairments. Our objective was to investigate the pattern of cognitive impairment in different neuropsychological domains up to a year after ischaemic stroke. We included prospectively collected data from an observational database of stroke patients at the National Hospital for Neurology and Neurosurgery, Queen Square, London, UK. Patients were categorised into temporal groups according to the time between the index stroke and neuropsychological profiling. The prevalence of impairment in different cognitive domains was then compared between these categories. The final cohort consisted of 209 patients. Frontal executive function, perceptual and nominal skills all showed a strong trend, with levels of impairment of approximately 30 % at < 1 month and less than half this at > 3 months (p < 0.05). Speed and attention was the most impaired domain, but had the greatest trend for decreasing impairment, from 72.4 % acutely to 37.9 % after 3 months (p < 0.01). By contrast, we found that impairment in visual and verbal memory showed no statistically significant change over time. Our results suggest a domain-specific improvement in cognition after ischaemic stroke. Early assessments may overestimate longer term cognitive deficits, particularly in speed and attention and perceptual functions. The domain-specific improvement patterns may help to inform long-term rehabilitation plans, which should not be based solely on cognitive assessments undertaken within the first month after stroke.