Magnetic Resonance Imaging is a radiation-free method of taking pictures of the brain. It shows only the structure of the brain, but can help us make sure that study participants are in the right trial (screening) and that they are safe to continue to have the trial medicine. MRI cannot diagnose dementia on its own, and is not sensitive to improvement or deterioration in people's memory or thinking.

PET scans use tiny amounts of radioactive dye to identify changes in the proteins in the brain They can be useful to get a definitive diagnosis and many of our clinical trials require this kind of scan before people can participate. Usually, only people with a definitive diagnosis by lumbar puncture or PET scan can participate in studies on early-stage Alzheimer's.

Pen-and-paper tests can help us diagnose the diseases underlying dementia and monitor people's progress during a study. These vary in difficulty and we can often make allowances for hearing or other difficulties. These are nearly always completed with a researcher by your side to keep you on track. Sometimes these are completed on a computer or tablet, and people are always given help with this if needed.

An ECG is used to measure electrical conduction in the heart. We do these regularly as part of the screening process for clinical trials to make sure there are no hidden abnormalities, and we often conduct them as part of our safety followup within studies.

Blood sampling is one of the routine investigations in any clinical trial, including blood tests examining the function of other organs (kidney and liver function for example). Sometimes we need to measure the levels of a particular medicine in the blood, to examine how it builds up and is broken down (called Pharmacokinetics). Sometimes new types of research blood samples can help us detect diseases like Alzheimer's earlier than, for example, MRI brain scans.

Lumbar puncture (sometimes known as an "LP" or "Spinal Tap") is one of the procedures people often have clinically in order to gain a definitive diagnosis of Alzheimer disease. This video from the Alzheimer's Society UK, described what's involved in the procedure. LP is used to take a sample of Cerebro-spinal fluid (CSF) from the bottom of the back, below where the spinal cord ends. This fluid can then be analysed using modern techniques to detect the abnormal proteins which are a hallmark of Alzheimer's.

For some studies we conduct genetic testing in order to establish people's risk of Alzheimer's disease. Some of this information can also be used to establish the risk of adverse reactions to study medicines. Genetic testing is not available outside of established, ethically-approved research studies.