Diagnosing Epilepsy & Seizure Disorders in Children
At the Pediatric Epilepsy Program, part of NYU Langone’s Comprehensive Epilepsy Center, experts from Hassenfeld Children’s Hospital at NYU Langone have the resources and experience to diagnose the various types of epilepsy and seizure disorders that occur in children.
A seizure is an excessive surge of electrical activity in the brain that can cause a variety of symptoms, depending on which parts of the brain are involved. Symptoms may include a sudden and involuntary jerk of a hand, an arm, or the entire body. Children having a seizure may describe smelling burnt rubber, or they may have a strange feeling in the stomach, hear a ringing sound that becomes louder, or stare into space.
Seizures can last for a few seconds up to several minutes. Some children may experience an aura, or warning symptoms, just before a seizure begins. An aura may involve smells, emotions, or mental experiences, such as a sense of déjà vu or out-of-body feelings. People experiencing an aura may also notice visual changes, such as blind or dark spots, bright lights, or a distortion in the shape or size of objects. Children may describe hearing sounds or voices.
Any person at any age can develop epilepsy and seizures. Epilepsy is more common in young children and in people older than age 55. Three million people in the United States have epilepsy.
To diagnose epilepsy in children, our doctors start with a medical history and physical examination. Additional diagnostic tools include a neurologic examination, electroencephalography, imaging tests, and genetic testing.
Medical History and Physical Examination
Because doctors seldom witness a child’s seizures, they compile a detailed medical history to help diagnose epilepsy and differentiate it from other conditions.
Epilepsy specialists at Hassenfeld Children’s Hospital at NYU Langone conduct a physical exam and ask you and your child questions about their seizure, including the following:
- How did the seizure begin? Was there a trigger?
- How long did the seizure last?
- Did a lack of sleep or unusual stress precede the episode?
- Was your child recently ill?
- Has your child taken any medications, including over-the-counter medications, alcohol, or illegal drugs?
- What was your child doing immediately before the attack? Were they lying down, sitting, standing, rising from a lying position, or exercising?
- Did your child lose consciousness or become mentally or physically impaired?
- What kind of movements were involved—for example, jerking, automatic chewing or hand movements, eye deviation or blinking, head turning to one side, loss of bladder control, or tongue biting?
- Did your child go to sleep or become confused after the seizure?
Recording information about a seizure can help your child’s doctor confirm that it was a seizure and help determine the type.
Because a seizure may be caused by a medical disorder, a physical exam is an important part of the first consultation. The exam and certain laboratory tests can tell your child’s doctor whether the liver, kidneys, and other organ systems are functioning properly.
This exam can help doctors determine whether brain function is impaired. During a neurological exam, a neurologist assesses mental functions, such as the ability to remember words and name objects.
The doctor then evaluates your child’s muscles, senses, reflexes, gait, and coordination. This helps identify patterns of weakness or sensory loss and detect subtle signs of a neurological problem.
The doctors may order one or more tests to help diagnose epilepsy and seizure disorders.
If a doctor suspects epilepsy is causing your child’s symptoms, an electroencephalography, or EEG, may be performed. This is the most specific test for diagnosing epilepsy, because it records the electrical activity of the brain.
EEG is a safe and painless procedure in which electrodes are applied to the scalp with a special paste or removable glue. The electrodes are connected by wires to an EEG machine that records electrical activity in the brain for 20 to 40 minutes.
Because the room is quiet and often dimly lit, your child may fall asleep during a routine EEG. This is ideal for diagnosis, because an EEG that measures brain activity while your child is both awake and asleep may provide additional information.
During the EEG, a technologist may ask your child to open and close their eyes several times, shine flashing lights into the eyes, or ask your child to breathe rapidly or deeply. Sometimes a doctor asks your child to stay awake for the entire night before the EEG is performed. Sleep deprivation can increase the likelihood that epileptic spikes may be recorded.
Sometimes the results of a routine EEG are normal or reveal only minor, nonspecific findings. In some people, brain waves that indicate epilepsy occur only once every few hours or only after an hour of sleep, and a routine EEG may not capture them. Your child’s doctor may want an extended recording that includes long periods of wakefulness and sleep.
An ambulatory EEG can record up to 72 hours of brain activity with a special recorder. This recorder, which is slightly larger than a smartphone, allows your child to go about their regular routine. It can be worn on the waist, with the wire running either underneath or outside of your child’s shirt.
Ambulatory EEG can last from 24 to 72 hours. The doctor may ask you or your child to keep a diary of activities during the testing period. Most recorders have an “event” button that your child can press if they experience symptoms of a seizure, such as feeling spacey or confused.
Video EEG monitoring allows the doctor to view your child’s behavior and brain activity at the same time. Having access to this data enables the doctor to see the correlation between seizure activity in the brain and your child’s symptoms and actions during the seizure.
Using video EEG, your child’s doctor can confirm whether they are having an epileptic seizure and, if so, what type it is and where it originates in the brain.
Video EEG recordings can be used whether your child is in the hospital or at home. When your child is in the hospital, doctors can safely induce a seizure and generally obtain better results than when waiting for a seizure to occur at home.
Doctors use a variety of different imaging tests to help pinpoint the cause of your child’s epilepsy.
In an MRI scan, a magnetic field and radio waves create computerized 2D or 3D images of the brain. A doctor may use this scan to better view the structure of the brain and look for any problems that may be causing the seizures.
A CT scan is a type of X-ray that creates detailed images of tissue and internal organs. CT scans can help doctors identify any brain abnormalities that might be causing seizures, such as scar tissue, tumors, or malformed blood vessels. They can also identify spinal fluid circulation problems.
CT scans are not as detailed as MRI scans, but they are performed quickly and can be helpful during emergencies.
Single-Photon Emission CT Scans
Single-photon emission CT scanning is an imaging tool that reveals blood flow in the brain.
During the test, a small amount of a radioactive compound is injected into a vein in your child’s arm. This material flows into different regions of the brain, and the particles it emits are measured. A large number of particles indicates more blood flow in a certain area.
The results of the test are displayed as a picture on a computer monitor, with different colors representing different levels of blood flow. If the scan is obtained during or immediately after a seizure, it may show increased blood flow in the area of the brain where the seizure occurred.
Computers can compare a baseline single-photon emission CT scan to one obtained immediately after a seizure to better show where the seizure originated in the brain.
A PET scan uses small amounts of radioactive glucose, or sugar, to create a detailed image of the brain. It enables a doctor to view blood flow and brain cell activity and to determine how well the brain metabolizes sugar.
This helps your child’s doctor determine how well the brain is functioning and identify the area of the brain in which focal seizures occur. Areas that do not use sugar well are often the same parts of the brain where these seizures occur.
Magnetic Resonance Spectroscopy Scans
Magnetic resonance spectroscopy uses an MRI machine to analyze the molecular components of tissue in a particular area of the brain. This helps doctors differentiate a seizure from another condition, such as a metabolic disorder, tumor, or stroke. It also gives doctors another way to view the tissue that may be causing seizures.
Functional MRI Scans
Functional MRI uses a standard MRI machine to identify brain function during specific tasks. The test measures changes in oxygen and blood flow to a particular area of the brain during a given task.
During this test, the doctor may ask your child to perform a task repetitively, such as reading a short passage or speaking simple words. The area of the brain used for these tasks is then highlighted on the scan.
By analyzing this data, the doctor can pinpoint areas of the brain that are essential for language or memory, which is important when considering surgical treatment of seizures.
Magnetoencephalography is an imaging technique used to identify and analyze brain activity. It does so by recording and measuring magnetic fields generated in the brain.
Detectors placed near the head record magnetic waves between seizures, which are then mapped in three dimensions on an MRI or CT image of your child’s brain. This test can help doctors focus on the part of the brain where the seizure is taking place, and view it in three dimensions. It can also help map the areas of the brain responsible for movement, the senses, and language.
Electrical Source Imaging
Electrical source imaging uses high-density EEG recording. It does this through a net of 128 to 256 sensors placed over the head, combined with MRI brain imaging and mathematical models to map the brain areas responsible for generating epileptic activity. An outpatient test similar to a regular EEG, it lasts about an hour, recording activity that occurs between seizures, known as interictal activity. Our experts analyze the data to understand the source of the activity in the brain and to help plan surgery for the treatment of poorly controlled seizures.
Genetic testing can help our doctors determine the cause of your child’s epilepsy. Information from genetic testing may determine what anti-seizure medications to prescribe. It can also help doctors better understand the long-term outcome of a diagnosis.
Our doctors may use an epilepsy gene panel, which evaluates the most common genes associated with epilepsy, or they may analyze your child’s chromosomes to look for irregularities associated with epilepsy. Another genetic testing option is whole exome sequencing. This approach assesses the entire DNA code to look for gene mutations linked to epilepsy. Our doctors typically analyze DNA from a child’s blood samples. In some cases, we analyze DNA from a saliva sample.
Sometimes, we suggest genetic testing of the parents to better understand the cause of a child’s epilepsy.