An electroencephalogram (EEG) is a medical test that measures electrical activity in the brain using small electrodes attached to the scalp. The test produces a recording of brain wave patterns that helps doctors diagnose conditions affecting brain function, including epilepsy and seizure disorders, sleep disorders, brain injuries, tumours, and other neurological conditions. The test is painless and non-invasive, typically taking 30-60 minutes. Patients may be asked to breathe deeply, look at flashing lights, or sleep during the test to observe brain responses under different conditions. EEG services are available at hospitals and specialized clinics across Canada, with testing covered by provincial health insurance when ordered by a physician. Wait times vary depending on urgency and regional healthcare capacity.