When you or someone you love has had a seizure for the first time, it can be frightening. Naturally, you want to know as soon as possible what caused it. But making a diagnosis of epilepsy often isn’t a quick process. Finding answers usually involves several exams and tests.
Your doctor will want a complete medical history. It’s the most important piece in making a diagnosis of epilepsy. Your doctor needs to know everything that happened before, during, and after the seizure. As soon as you can after having had a seizure, write down everything you recall about what you were doing before it occurred, what you experienced during it, and how you felt afterward. Epilepsy.com has a good list of information about your seizure that your doctor needs.
It’s extremely helpful to have an eyewitness account from someone else who witnessed your seizure. Ask them to go with you to the doctor’s office; if they can’t, ask them to give their account of your seizure by phone to the doctor or nurse.
Your doctor will also do a thorough medical exam, looking for signs of other conditions that can cause seizures and to evaluate how well your brain and the rest of your nervous system are functioning.
Based on the findings of your history and physical exam, your doctor will order tests to determine a cause for your seizures. One of the most important tests in diagnosing epilepsy is an electroencephalogram, or EEG, which looks at the pattern of electrical activity in your brain.
Small metal disks are attached to your scalp. Each monitors a different region of the brain, sensing electrical activity and transmitting it to a machine that records it. An EEG has one line for each of the electrodes on your scalp. Each one looks a little bit like the tracings of a seismograph—the instrument that detects movement of the earth.
The EEG shows the pattern of electrical activity in the brain. Abnormal patterns result from a number of conditions, including head trauma, strokes, and brain tumors. The patterns that suggest epilepsy include spikes in electrical activity, sharp waves, and spike-and-wave activity. Both the pattern of activity and the location in the brain help identify whether epilepsy is causing seizures.
Your doctor may also order blood tests, to look for medical conditions that cause seizures, and a brain scan, to look for tumors or infections that can cause seizures. This is typically either a CT (CAT) scan or a magnetic resonance imaging (MRI) scan.
Your doctor may also order a test of your heart (an electrocardiogram or EKG) or a spinal tap. Also called a lumbar puncture, a spinal tap removes a very small amount of the fluid inside your spinal column to see if it contains abnormal cells.
Your doctor may send you to see a neurologist, as well, who will do a specialized neurological exam to look for abnormal brain function.