Anyone who experiences a seizure should be evaluated by a specialist to find the cause. Repeated seizures will lead to a diagnosis of epilepsy, but determining the reason for the seizures will aid in the development of a treatment plan (see Doctors Who Treat Epilepsy).
Diagnosis begins with a complete physical examination as well as a medical and family history. (Because seizure disorders run in families, having a close relative with epilepsy increases a person’s risk of having or developing the disorder.) A patient will be asked to describe carefully the experience of the seizure, since the symptoms can provide important clues as to the type of epilepsy he or she has.
The doctor will then order some tests, including:
An electroencephalograph (EEG) measures electrical activity in the brain. People with epilepsy often have abnormal electrical patterns even when not experiencing a seizure. EEGs can be even more helpful when performed soon after a seizure, when electrical activity is still abnormal. Magnetoencephalography (MEG) is another test that also localizes epileptic discharges in the brain using magnetic fields.
Imaging tests can reveal internal structures and functions of the brain. Computerized tomography scans (also called CT scans) and magnetic resonance imaging (MRI) scans produce tiny “slices” of images of the brain that can be viewed as three-dimensional views. These scans can detect structural abnormalities as well as tumors, providing important clues to the source of the epilepsy. Positron emission tomography scans (PET scans) and functional MRI (fMRI) scans can provide a real-time view into the brain's activity and help locate the focal points for seizures. They can help determine whether a patient is a good candidate for surgery and can be used to guide surgery (see Surgery for Epilepsy).
Blood tests and developmental tests may be helpful in diagnosing epilepsy in children.
Medication is the first step in a treatment plan for epilepsy, and it is often very effective in controlling seizures. There are several different types of epilepsy medication, and it’s common for a patient to try a few different medicines before finding one that works to control seizures. Medication works to control seizures in as many as 80 percent of epilepsy patients. These patients remain under medical treatment for life.
If three different medications fail to control seizures, it’s unlikely that another medication will help. Since uncontrolled seizures can lead to brain damage and even death — and even mild seizures can cause social isolation and emotional distress — patients whose seizures can’t be medically controlled may be evaluated for surgery.
Localizing the Seizures
The first step in determining whether a patient is a good candidate for surgery is finding out exactly where the seizures start, a process called “localizing” the seizures. If the seizures begin in one small part of the brain, surgery on that part may be a cure for epilepsy or may greatly reduce the number and severity of the seizures. To localize the seizures, a multidisciplinary team consisting of neurologists, neurosurgeons, neuroradiologists, neuropsychologists, nurse specialists, language therapists, and occupational and physical therapists works together to find evidence that points to a particular part of the brain as the source of seizures. These teams are found at major medical centers and include the Comprehensive Epilepsy Center at NewYork-Presbyterian/Weill Cornell Medical Center. (See Doctors Who Treat Epilepsy.)
If a patient’s seizures can be localized, the team may recommend surgery as the best chance for controlling seizures and even curing the epilepsy (see Surgery for Epilepsy).
Reviewed by Theodore Schwartz, M.D.
Last reviewed/last updated: September 2023