Background: Arterial disease of the legs causes symptoms such as pain when walking and may ultimately lead to a leg amputation. Many older people with arterial disease of the legs also have problems with their thinking and memory. Blood flow in the brain may be altered in these people and may be a cause for memory and thinking problems. Aim: The aim of this project is to investigate whether people with arterial disease of the legs have altered blood flow in the brain causing problems with memory and thinking. Research plan: Twenty people with arterial disease of the legs causing pain while walking and twenty healthy people will have a series of non-invasive assessments. Arterial disease in the legs will be measured using ankle blood pressures before and after walking. Blood flow in the brain will be measured using ultrasound whilst performing memory and thinking tests. Results will be compared between the people with arterial disease in the legs and the healthy people to see if there are any differences in blood flow to the brain and memory and thinking. Benefits to society: This project will help determine if there is a link between arterial disease of the legs and memory and thinking problems caused by altered blood flow in the brain. It will enable future research in people with cognitive impairment caused by altered blood supply to the brain and to prevent confusion and further memory and thinking problems in people undergoing surgery for arterial disease of the legs.