What Is Epilepsy?

Doctor pointing at brain scanEpilepsy—also called seizure disorder—is a disease of the brain that causes recurrent, unprovoked seizures. When someone has epilepsy, the brain’s electrical functions are disrupted by abnormal bursts of electrical energy that are more intense than usual.

These disruptions in electrical activity may cause abnormal sensations such as numbness, strange taste or smell, a loss of consciousness or uncontrolled bodily movements. Often, the person is only partially aware of the seizure.

There are two main types of epilepsy:

Generalized epilepsy: Abnormal electrical discharges that involve all areas of the brain at the beginning of the seizure are called generalized seizures. In many generalized epilepsies, the brain looks completely normal and has no structural abnormality to explain the seizure. This type of epilepsy is thought to be caused by a genetic (inherited) predisposition.

In some cases, generalized epilepsies are associated with brain abnormalities, which are sometimes caused by:

  • Brain infections
  • Head injuries
  • Lack of oxygen

Focal epilepsy: Abnormal electrical activity that starts in a small area in the brain and spreads to the rest of the brain is called focal seizure. Focal epilepsies are often caused by a lesion (or scar) detectable on an MRI scan. Typical lesions that cause focal epilepsy are:

  • Hippocampal sclerosis (hardening of the hippocampus)
  • Scarring after stroke or trauma
  • Small area of disorganized brain tissue
  • Benign brain tumor
  • Malformed blood vessel

When seizures are triggered by something other than abnormal electrical activity in the brain, they are not caused by epilepsy. Non-epileptic seizures may be caused by:

  • Low blood sugar
  • Infections
  • Drug overdose or withdrawal
  • Emotional stress

Northwestern Medicine Comprehensive Epilepsy Center

The Comprehensive Epilepsy Center at Northwestern Memorial Hospital maintains the highest designation by the National Association of Epilepsy Centers. We work together to determine how to best treat your seizures in a way that minimizes significant side effects and maximizes your quality of life.

The Center is staffed with a multidisciplinary team1 that includes neurologists, neurosurgeons, psychiatrists, psychologists, and specialized nurses and EEG technicians. We see our patients by referral to allow continuation of care with the local neurologist and primary physicians. Services available include:

  • Second opinions regarding your seizure or epilepsy diagnosis
  • Comprehensive epilepsy care
  • Inpatient epilepsy monitoring
  • Stereo EEG evaluation
  • Epilepsy surgery, including minimally invasive resections and brain stimulation
  • Epilepsy treatment tailored to women
  • Clinical research trials

Find out more about our programs:


The board-certified neurologists at Northwestern Medicine Lake Forest Hospital are trained in the diagnosis and treatment of nervous system disorders, including diseases of the brain, spinal cord, nerves and muscles. They diagnose and treat patients with a full range of neurological disorders, including epilepsy and seizure disorder.

Comprehensive Seizure and Epilepsy Program at Northwestern Medicine Central DuPage Hospital and Northwestern Medicine Delnor Hospital
Epilepsy—also called seizure disorder—is a condition that can have many causes and can occur at any age. The Comprehensive Seizure and Epilepsy Program at Northwestern Medicine Central DuPage Hospital and Northwestern Medicine Delnor Hospital uses a multidisciplinary approach to diagnose, manage and treat this medical problem. The program also seeks to address the many consequences of living with epilepsy so that you can maximize your quality of life.

Related Resources


  • Video-EEG Monitoring: EEG portion of the test looks at electrical activity of the brain and the video recording shows how the body responds during a seizure.
  • Wada Testing: Learn more about this test, which examines each side of your brain.
  • Specialized Treatment for Epilepsy: The Northwestern Medicine Comprehensive Epilepsy Center maintains the highest designation by the National Association of Epilepsy Centers.


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