Imagine being told you have dementia and that it could have been treated if it was detected in the preclinical stage. We hope to identify the earliest signs of dementia through blood tests, smell tests and early tests of a person's thinking. Dementia is characterised by personality change, deficits in executive function, and language impairment. Successful treatment of dementia will require early detection and intervention, before major cell death in the brain has occurred. Understanding the earliest changes that occur in the brain and blood of people at high risk of developing dementia is the focus of this project. We hope to reveal the earliest changes that occur in the body to determine firstly, if we can identify early signs of dementia, and secondly, if we can identify therapeutic targets that can be modulated at this early timepoint to halt disease progression before it affects personality, behaviour, and executive function.