1. Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE1 7RH, UK
2. College of Applied Medical Sciences, University of Najran, Najran P.O. Box 1988, Saudi Arabia
3. NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester LE3 9QP, UK
4. University Hospitals of Leicester NHS Trust, Leicester LE1 5WW, UK