An electroencephalogram (EEG) is a non-invasive medical test that measures the electrical activity in the brain. This activity, often called brain waves, is produced by the communication between nerve cells (neurons) and is recorded as wavy lines on a computer screen or paper. The test uses small, metal discs, called electrodes, that are temporarily affixed to the child’s scalp to pick up these tiny electrical signals. A pediatric EEG is specialized to assess the unique and rapidly developing brain function of children. Since the EEG only records activity and does not send electricity into the brain, the procedure is safe and entirely painless.
Conditions Diagnosed by a Pediatric EEG
The primary reason a neurologist orders an EEG for a child is to investigate seizure disorders, such as epilepsy, by identifying abnormal bursts of electrical activity. The test helps determine the type of seizure a child is experiencing and whether the abnormal activity begins in a localized area or across both sides of the brain. Recognizing a specific pattern of electrical activity can sometimes point toward an epilepsy syndrome, which provides insight into the child’s prognosis and optimal treatment plan.
Beyond seizure disorders, the EEG is a valuable tool for evaluating a range of other neurological concerns in children. It can be used to assess the cause of fainting spells, headaches, and certain behavioral disturbances. Neurologists also use the EEG to evaluate developmental delays, language problems, and sleep disorders like sleep apnea. In cases of severe brain injury or infection, such as encephalitis, the EEG helps monitor overall brain function and recovery.
How to Prepare Your Child for the Test
Successful completion of a pediatric EEG begins with careful preparation at home to ensure clear and reliable data is collected. Parents should wash their child’s hair thoroughly the night before or the morning of the test, using only shampoo and clear water. It is important not to apply any oils, gels, conditioners, or hairsprays, as these products can interfere with the electrodes’ ability to make good contact with the scalp.
If the neurologist requires a sleep study, specific instructions regarding sleep deprivation must be followed closely to ensure the child can fall asleep during the test. For instance, children under two years old may be woken an hour or two earlier than normal, while older children may have a significantly altered bedtime and wake-up schedule. Parents should also make sure the child eats a meal or snack an hour or two before the appointment to stabilize blood sugar levels. Avoid all caffeine and high-sugar foods for up to 24 hours prior to the test. Discussing the test in an age-appropriate, reassuring manner helps reduce anxiety, and bringing a favorite toy or blanket can provide comfort during the procedure.
The Step-by-Step EEG Procedure
Once the child is in the testing room, a trained technologist will begin the setup, which is the longest part of the procedure, often taking around 30 minutes. The technologist first uses a measuring tape to mark specific locations on the scalp where the electrodes will be placed according to a standardized system. Each marked spot is then gently rubbed with a mild, gritty lotion to clear away dead skin and oils, which allows for better signal transmission.
The technologist then secures around 20 small metal electrodes to the scalp using a conductive paste or a mild, water-soluble glue. These electrodes are connected by wires to the EEG machine, which records the electrical activity onto a computer. The actual recording phase for a routine EEG typically lasts between 20 to 45 minutes, though the total appointment time is usually 60 to 90 minutes.
During the recording, the technologist may ask the child to perform certain “activation” procedures to provoke abnormal brain activity. These may include deep, rapid breathing (hyperventilation) or looking at a strobe light with their eyes closed (photic stimulation). The child may also be asked to open and close their eyes, and often, the technologist will encourage the child to relax or sleep, as certain electrical patterns only appear during these states.
What the EEG Results Indicate
After the recording is complete, the electrodes and the conductive paste are removed from the child’s scalp, and the child can return to their normal activities. The recorded patterns of brain waves are then analyzed by a neurologist or a pediatric neurologist who specializes in interpreting this complex data. The neurologist looks for features that stand out, such as “spikes” or “sharp waves,” which are sudden, transient electrical bursts often associated with epilepsy.
The results are also evaluated for general disruptions in the normal brain rhythm, known as background activity, which could suggest a structural problem or the effects of medications. A final report is then compiled, which typically takes several days to a week to reach the referring physician, though urgent findings are communicated immediately. An abnormal EEG does not automatically confirm an epilepsy diagnosis, and the results are always considered alongside the child’s clinical history and other neurological tests.