EEG Testing Process
Preparing for an EEG Procedure
The following sections on EEG monitoring, interpretation and results include information for audiences undergoing the EEG tests in a healthcare setting. The best way to prepare for a test is always to ask the test administers for specific preparation instructions. Instructions for preparation can vary by use case — for example, EEG recordings for consumer research, academic research or performance and wellness may require subjects to be active instead of lying down.
Companies like EMOTIV have pioneered advances in EEG technology that make conducting, processing and interpreting tests faster and more convenient. EMOTIV’s mobile and wireless EEG headsets can be set up in less than five minutes, and they enable the participant to move freely instead of confining them to a testing facility.
In advance of an EEG test, tell the professional administering the test — whether that’s a doctor, employer or researcher — about any regular medications you take. It’s recommended that you wash your hair the night before the procedure and leave it free of any products. Avoid drinking or eating any caffeine at least 8 hours before the test. If you have to sleep during the EEG procedure, you may be instructed to limit your sleep the night before to ensure your brain can relax properly during the test.
EEG Monitoring
You’ll feel no pain or discomfort during an EEG procedure. During a clinical EEG procedure, you’ll be lying on a bed or a reclining chair and instructed to close your eyes. An EEG technician measures your head and marks where to apply the leads.
When the test begins, the electrodes record your brainwaves and sends the activity to a recording machine. The EEG machine then converts the data into a wave pattern for interpretation. After the recording is finished, the technician will remove the electrodes from your scalp.
Routine EEG tests in scientific or clinical settings take 30-60 minutes to complete, including around 20 minutes of initial set-up time. EEG tests conducted for consumer, individual performance and workplace research can be shorter or longer in duration depending on the testing purposes. EMOTIV’s wireless EEG headsets support quicker set up for these use cases (less than five minutes).
There should be no recovery time needed after a procedure. If you’ve taken a medication that has caused drowsiness in order to sleep during the test, the test administrator may recommend waiting at the facility until the effects have worn off or have someone drive you home.
EEG test side effects are rare. The electrodes don’t produce any sensations; they only record brain activity. Persons with epilepsy may experience a seizure from stimuli such as flashing lights during the procedure. A seizure during an EEG test is nothing to be scared of — it can actually help doctors diagnose the type of epilepsy and accordingly tailor the treatment.
EEG Interpretation and Procedure Results
If you’ve been recommended an EEG test for clinical reasons, your test results will be interpreted by a doctor who specializes in the nervous system. The neurologist will study the recording for normal and abnormal brain patterns. Brain wave patterns are very recognizable by the characteristics of their waveforms. For example, a burst suppression pattern, which is often observed in patients with inactive brain states such as from coma or general anesthesia, shows brief spikes (the burst) alternating with periods of flatness (the suppression).
Different types of epilepsy are characterized by distinct EEG patterns. A spike-wave pattern — a generalized, symmetrical EEG pattern — is often observed during an absence seizure, where a person experiences a brief loss of consciousness. A partial focal seizure, in which seizure activity only affects one area of the brain, is characterized by a low-voltage, fast rhythm pattern that appears in the EEGs data channel associated with that area.
The neurologist then sends the EEG measurement back to the doctor who ordered the test. Your doctor may schedule an appointment to review the EEG images and discuss the results with you. Depending on your condition, you may be recommended a service called EEG neurofeedback or biofeedback as a follow-up. For example, people looking to strengthen brainwave patterns associated with focus might engage in neurofeedback therapy for ADHD.
Biofeedback therapy helps subjects control involuntary bodily processes. A subject experiencing, for example, high blood pressure, can view their bodily measurements on a monitor that’s receiving data from electrodes on their skin. Monitoring this activity helps teach relaxation and mental exercises that can alleviate symptoms.
Similarly, Neurofeedback relies on EEG to train the brain to function better. During this training, the patient is hooked up to an EEG machine and is viewing their brain activity in action. This often resembles a type of video game where the patient is “playing” the game with their brain to control their brain activity. The patient tries to improve the brain frequencies associated with brain dysfunction, the same way an athlete works on a weak muscle. EEG neurofeedback is often recommended for conditions such as epilepsy, bipolar disorder, ADHD and autism. While it can help these disorders, it cannot cure them.