Diagnosis of epilepsy usually begins with a medical history and physical examination. Because there are many different types of seizures, some of which are not related to abnormal brain activity, it is important that a physician identify the type of seizure a patient has had. The physician may ask questions that relate to:

• What sensations the patient feels before, during or after a seizure
  
  
• How long the seizure normally lasts
  
  
• Which side of the body is most affected during a seizure
  
  
• To what extent the patient experiences a change in or loss of consciousness
  
  
• Whether the patient feels any pain before, during or after the seizure

If patients do not remember the nature of their seizures, a physician may ask questions of the patient’s caregiver, parents or others who have witnessed the seizures. The physician may also ask about any other conditions or symptoms the patient has, any medications the patient may be taking, and whether the patient uses alcohol or drugs.

In addition to the medical history and physical examination, a physician may conduct tests to assess which areas of the brain may be involved in the seizures. These tests may include:

• Electroencephalogram (EEG). An EEG is one of the most common tests that a physician may conduct following a seizure. During an EEG, electrical activity in the brain is monitored through electrodes placed on the scalp. People with epilepsy may show abnormally slow frequencies or spikes and other disruptions, even when they are not having a seizure. A physician may request that the EEG be performed while the patient is sleeping to get an accurate picture of normal brain activity.
  
  
• Computed axial tomography (CAT) scan. A CAT scan is a noninvasive or minimally invasive test that uses a rotating x-ray device to create detailed cross-sectional images of different body parts, including the brain. It can be used to identify tumors or other abnormalities in the brain that may be causing a patient’s recurring seizures.
  
  
• MRI (magnetic resonance imaging). An MRI is a noninvasive procedure that uses powerful magnets and radio waves to produce clear, cross-sectional and three-dimensional images of the body’s tissues. Like the CT scan, it can be used to view the brain and identify abnormalities. A special kind of MRI, called a functional MRI (fMRI), can be used to allow physicians to see how the brain functions. During an fMRI, the patient may be asked to perform a task while the machine scans the brain and records its activity. This can then be used to gauge which parts of the brain are functioning abnormally.
  
  
• Blood tests. Blood samples may be taken to screen for conditions such as diabetes, infection or anemia, which may be the causing a patient's recurrent seizures. Blood tests may also be used to identify metabolic or genetic disorders that may be related to the seizures.