4. Having a lumbar puncture
A lumbar puncture is used to take a sample of the cerebrospinal fluid from the lower back. This fluid flows around the spinal cord and the brain, and clears waste products. Levels of certain proteins in the cerebrospinal fluid reflect what is happening in the brain.
Alzheimer’s disease is characterised by the abnormal clumps of proteins called amyloid and tau in the brain. These changes are reflected in the levels of proteins in the cerebrospinal fluid, so a lumbar puncture can indicate whether the brain is affected by Alzheimer’s disease.
A special needle is used to take the sample of fluid from the lower back. Afterwards the person who had the sample taken is often asked to have a short rest. It is common for people to experience headaches or back pain after a lumbar puncture but these side effects usually settle over time. If people experience a headache after lumbar puncture, it typically starts 24-48 hours after the procedure.