Diagnosis

Your doctor will ask for a detailed description of the seizures and conduct a physical exam. Tests may include:

• Electroencephalography (EEG). This painless procedure measures waves of electrical activity in the brain. Brain waves are transmitted to the EEG machine via small electrodes attached to the scalp with paste or an elastic cap.

  Rapid breathing (hyperventilation) during an EEG study can trigger an absence seizure. During a seizure, the pattern on the EEG differs from the normal pattern.

• Brain scans. In absence seizures, brain-imaging studies, such as magnetic resonance imaging (MRI), will be normal. But tests such as MRI can produce detailed images of the brain, which can help rule out other problems, such as a stroke or a brain tumor. Because your child will need to hold still for long periods, talk with your doctor about the possible use of sedation.