Various medical conditions can result in seizures. Before diagnosing epilepsy, a physician will consider other
possible causes of the seizures. A high fever or a metabolic disturbance could cause seizures to occur. For example, an electrolyte disturbance as a result of severe diarrhea or vomiting, or a glucose imbalance cause
by low blood sugar, may result in seizures. Blood tests are sometimes used to find medical conditions, other than epilepsy, that may be causing seizures.
In addition to a thorough physical examination, the procedures used to establish a diagnosis of epilepsy usually includes a medical history and diagnostic tests.
Medical history is important in a physician’s assessment. Typically, it involves a family health history and a detailed description of the characteristics, onset and frequency of the seizures. Determining the type of seizure an individual is having is valuable in both the diagnosis and the prescribing of the appropriate treatment.
Diagnostic tests usually include an electroencephalogram (EEG). An EEG is used to record the brain’s electrical activity and it is an important tool in the diagnosis of epilepsy. Neuroimaging tests are often used to provide pictures of the brain. Computed tomography (CT) and magnetic resonance imaging (MRI) scans provide pictures of the brain structures.
Other neuroimaging tests such as magnetic resonance spectroscopy (MRS) and positron emission tomography (PET) show how the brain functions and are used to evaluate the possibility for epilepsy surgery.
It is important to note that sometimes a diagnostic test does not detect abnormalities. For example, a person
with epilepsy may have a normal EEG because abnormal activity is not present during the recording, or the activity is too deeply located in the brain to be recorded.
MORE ON DIAGNOSTIC TESTING
An EEG is a painless, non-invasive test that is used to measure a person’s brain wave pattern. The EEG recordings can detect abnormalities in the brain’s electrical activity.
CT SCAN (Computed Tomography)
A CT (or CAT) scan is used to detect physical conditions in the brain that may be causing seizures such as tumors or scar tissue.
MRI (Magnetic Resonance Imaging)
An MRI is used to provide structural information such as the presence in the brain of tumors, scar tissue, or abnormal blood vessels.
MRS (Magnetic Resonance Spectroscopy)
Essentially an MRI with a different computer program, the MRS provides information about chemical activity in the brain. This information can be used to detect metabolic abnormalities in the brain during, after, and in between seizures.
PET (Positron Emission Tomography)
PET scanning produces three-dimensional computer images of the brain processes at work.
SPECT (Single Photon Emission Computed Tomography)
This test helps to locate the site where the seizure begins.
MSI or MEG (Magnetic Source Imaging or Magneto encephalography)
This test is used to assess the function of brain tissue. It is similar to the EEG, but magnetic rather than
electrical brain waves are recorded in a three-dimensional fashion through sensors located in a machine placed near the person’s head.