Diagnosing Epilepsy

Epilepsy Foundation » About Epilepsy » Diagnosing Epilepsy » First Steps to Diagnosis 

The First Steps to Diagnosis

A seizure is the outward sign of a malfunction in the electrical system that controls the brain. A single seizure can have many causes, such as high fever or lack of oxygen or poisoning; seizures that occur more than once, without a special cause, are called epilepsy (also called a seizure disorder).

Seizures may be convulsions, brief stares, muscle spasms, odd sensations, or episodes of automatic behavior and altered consciousness.

Provide Information to Help the Doctor

If you have had a seizure and you seek medical help, your doctor will want to know:

  • Was the seizure caused by a short-term problem (like fever or infection) that can be corrected?
  • Was it caused by a continuing problem in the way your brain's electrical system works?
  • Is there anything about the structure of your brain that could cause seizures?
  • Was the seizure an isolated event, or does it mean that you have epilepsy?

Definitions:

  • Computerized tomography (CT): A scanning method that uses X-rays and computers to create images of the internal structure of the brain, produced at different levels, in a series of 'slices.'
  • Magnetic resonance imaging (MRI): An imaging method using magnets instead of X-rays. Produces detailed pictures of the internal structure of the brain.

Diagnostic Methods and Tools

The doctor's main tool in diagnosing epilepsy is a careful medical history with as much information as possible about what the seizures looked like and what happened just before they began. The doctor will also perform a thorough physical examination, especially of the nervous system, as well as analysis of blood and other bodily fluids.

A second battery of diagnostic tools include an electroencephalograph (EEG). This is a machine that records brain waves picked up by tiny wires taped to the head. Electrical signals from brain cells are recorded as wavy lines by the machine. Brain waves during or between seizures may show special patterns which help the doctor decide whether or not someone has epilepsy.

Imaging methods such as CT (computerized tomography) or MRI (magnetic resonance imaging) scans may be used to search for any growths, scars, or other physical conditions in the brain that may be causing the seizures. In a few research centers, positron emission tomography (PET) imaging is used to identify areas of the brain which are producing seizures.

Which tests and how many of them are ordered may vary, depending on how much each test reveals.