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 seizure medication actually have a diagnosis other than epilepsy!

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

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

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
    • 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: 
Amy Crepeau, MD | Epilepsy.com Diagnostics editor