Electroencephalogram is used in Polysomnography to monitor the brain-wave activity of sleep disorder patients. Electrodes are placed on your scalp and they will monitor the electrical impulses coming from the brain. It is a pain-free procedure and does not last long. This test will monitor your brain activity during your sleep to assess whether your brain is overly active during the night. As you are asked to sleep whilst this test is carried out, you may need to reduce your sleep time the night before to ensure you can sleep fully during the procedure. Equally, it is important that avoid any stimulants e.g. caffeine, before the test is carried out as this could affect the brain wave activity and reduce your chances of sleeping. Conducted with several other tests, Electroencephalogram will hopefully establish the root cause of your sleeping disorder and lead to an effective treatment. The doctors who conduct the test will talk you through the procedure and what you can expect from it.