The doctor usually orders a variety of tests to help make the epilepsy diagnosis. These include:

  • A brain wave test, also called an EEG (electroencephalogram), to look for changes in the brain's electrical patterns that are related to seizures.
  • Blood tests, to look for certain medical disorders.
  • Either a special x-ray of the brain, a CT scan (sometimes called a CAT scan), or an MRI scan (magnetic resonance imaging), to look for abnormal areas such as a tumor or infection.
  • Depending on the urgency of the situation, other tests also might be recommended, such as a lumbar puncture (also called a spinal tap), EKG (electrocardiogram, to check the heart), or a sleep test.

The results of these tests often appear completely normal in people with epilepsy. Normal test results do not mean that the seizures are not real or that epilepsy is not present.

Why is my doctor ordering other tests to evaluate my seizures?

Not all events that appear to be seizures truly are epilepsy seizures, which occur due to abnormal surges of electrical activity in the brain. Some people that have been treated with anti-seizure medication have a diagnosis other than epilepsy!

In fact, approximately 1 in 5 people who have not responded to anti-seizure medication and are admitted to an Epilepsy Monitoring Unit for evaluation of seizures are shown to have an alternative diagnosis.

While recording events with video EEG monitoring is considered the gold standard to diagnosing seizures and spells, other tests can be helpful as well for testing for seizures.

Test: Cerebrovascular Imaging, such as

  • MR or CT angiogram of the head and neck
  • Carotid ultrasound
  • Conventional Angiography

Possible Alternative Diagnosis:

  • Transient Ischemic Attack
  • Stroke
  • Vasculitis
  • Vascular malformation

Test: Cardiac Holter Monitor

Possible Alternative Diagnosis:

  • Cardiac arrhythmia

Test: Tilt Table/Autonomic Reflex Study

Possible Alternative Diagnosis:

  • Syncope or convulsive syncope due to
    • Vasovagal response
    • Orthostatic Hypotension
    • Postural Orthostatic Tachycardia Syndrome (POTs)
    • Autonomic neuropathy

Test: Overnight Polysomnography (Sleep Study)

Possible Alternative Diagnosis:

  • Parasomnias (Sleep related abnormal movements)
  • Sleep apnea

Test: Movement Disorder Physiologic Study

Possible Alternative Diagnosis:

  • Myoclonus
  • Tremor
Authored By: 
Carl W. Bazil MD, PhD
Joseph I. Sirven MD
Amy Z. Crepeau MD
Reviewed By: 
Brandy Fureman PhD
Thursday, October 21, 2021