The close relationship between stroke and dementia is an important health issue. Ischaemic stroke can facilitate the onset of vascular dementia as well as aggravate pre-existing cognitive decline. The onset of cognitive decline may become manifest immediately following the onset of ischaemic stroke, but often there is a delay in the development of cognitive decline after a stroke. This delay can be seen as a therapeutic time window allowing interventions to be applied to preserve cognition following stroke. Both neurodegenerative and vascular mechanisms are activated and probably result in overlapping processes within the neurovascular unit. This review focuses on the incidence and prevalence of cognitive decline following stroke, predisposing stroke aetiologies, pre-stroke decline, imaging factors and biomarkers. Outcomes are discussed in relation to timing of assessment and neuropsychological tests used for evaluation of cognitive decline in ischaemic stroke patients. Including such tests in routine evaluations of stroke patients after some weeks or months is recommended. Finally, an outlook on ongoing and planned intervention trials is added and some recommendations for future research are proposed.

Introduction: Multiple, complex interventions are increasingly tested in randomized, clinical trials without enabling a clear view of the strength of the intervention, especially its probability to influence outcome. Such interventions have to be strong enough to create group differences, be acceptable by patients, be realistically designed and deliverable within the health system, and ethical. If found to have a positive effect, it should have a sustainable effect after the trial is drawn to a close. It is necessary to adapt the intensity of the intervention to contrast with guideline-based treated controls and to ensure sufficient means to carry through to the end of the trial. Method: Using a multiple domain life-style based intervention in a randomized trial to prevent cognitive decline following stroke (ClinicalTrials.gov Identifier: NCT01109836), our focus was on nutrition and physical exercise in addition to risk factor management. We performed single component analysis as well as the use of a life-style summary score and a laboratory supported life-style summary score. Results: 80 participants in the intervention group and 87 in the control group completed the 12 months visit. We found a significant improvement in adherence to healthy lifestyle factors and adequately controlled physiological parameters as well as significant differences for both summary scores, all p <0.001. The summary scores includes the use of reduced milk and fat spreads, consuming fish ≥1/week, drinking alcohol 1-6 times/week, physical activity ≥90 minutes/week, body mass index <30 kg/m 2 and currently non-smoking. Laboratory values included blood pressure <140 / <90 mmHg, non-HDL-cholesterol ≥2.6 mmol/L and fasting blood glucose <7.0. mmol/L Conclusion: Complex interventions used for secondary prevention stroke trials have to be intense enough to become effective when comparing to treatment according to current guidelines.