How Long Does EEG Test Take? Electroencephalography
Electroencephalography (EEG) might seem complicated, but it is a safe and painless diagnostic tool that provides valuable insights into brain health. If you are being referred for unexplained seizures, fainting spells, sleep disturbances, or other neurological issues, an EEG can give your doctor important information to help with diagnosis and treatment.
In this blog, we’ll look closely at what an EEG involves and answer one of the most common questions patients have: “How long does EEG test take?” You’ll also learn about the different types of EEGs, what to expect during the procedure, and how to prepare for it.
What Is an EEG and Why Is It Done?
An EEG test estimates the electrical activity of the brain using small sensors (electrodes) placed on the scalp. A neurologist records and interprets these signals to detect any unusual patterns or irregular brain activity.
EEGs are most commonly used to evaluate:
- Epilepsy and seizure disorders
- Sleep disorders
- Brain injuries
- Encephalitis or inflammation of the brain
- Unexplained periods of unconsciousness
Unlike imaging tests like MRIs or CT scans, which provide structural information, an EEG gives a real-time view of how the brain is functioning.
How long does it take to do an EEG test?
How long does EEG test take depends on the type of EEG you’re having. While a routine session might wrap up in under an hour, more advanced options like ambulatory EEGs can last for a full day or more. Here’s a breakdown of the most common types and how long they typically take:
1. Routine EEG
- Duration: 20 to 40 minutes of actual recording
- Appointment time: Up to 60 minutes (including preparation)
- This is the most common EEG and is often done in an outpatient clinic. It may involve specific breathing exercises or light stimulation to provoke brain activity.
2. Sleep-Deprived EEG
- Duration: 60 to 90 minutes
- You’ll be asked to stay awake the night before for this test. Sleep deprivation can make brain abnormalities more noticeable. It includes both resting and sleeping segments to capture changes.
3. Ambulatory EEG
- Duration: 24 to 72 hours
- This type allows your brain activity to be recorded over an extended period while you go about your normal day. Electrodes are attached to a small portable recorder you wear at home.
4. Video EEG Monitoring (Inpatient)
- Duration: 24 hours to several days
- This test, done in a hospital setting, combines continuous EEG with video recording to correlate physical behaviour with brain activity. It’s typically used for seizure diagnosis or surgery planning.
5. Prolonged EEG
- Duration: Lasts 1.5 to 3 hours or more
- It’s recommended when more data is needed, especially to observe brain activity during wakefulness and sleep.
- Helps detect subtle abnormalities or possible seizure activity that a standard EEG might miss.
If you’re still wondering, “EEG test, how long does it take?” For most people, a standard outpatient EEG takes about an hour. However, longer EEGs may be needed to capture more data or monitor brain activity under specific conditions.
What to Expect During the Test
Whether you’re having a short or extended EEG, here’s what typically happens:
- Your scalp will be cleaned, and around 20 small electrodes will be placed using a special adhesive.
- You’ll lie in a quiet room while your brain’s electrical signals are recorded.
- The test is completely painless; no electricity is passed into your body.
- You may be asked to perform deep breathing or watch flashing lights.
- You may be encouraged to nap during the test if it’s a sleep EEG.
There’s no recovery time needed, and you can resume normal activities after a routine EEG unless you were sleep-deprived beforehand.
How to Prepare for an EEG
- Avoid caffeine for at least 8 hours before the test, as it may affect results.
- Wash your hair the night before and avoid applying any oils or sprays.
- Follow specific instructions if it’s a sleep-deprived EEG (such as staying awake overnight).
- Bring a list of medications you’re taking; some may affect your brain activity.
How Dr Miguel Ley Nacher Can Help You Understand Your EEG Results
Dr Miguel Ley Nacher, a renowned neurologist with extensive experience in diagnostic neurology, emphasises the importance of knowledge and precision in brain health.
He provides a personalised and compassionate approach to EEG testing. Each patient undergoes a thorough assessment, and EEGs are done and interpreted according to their individual needs, rather than solely based on test results. Patients often ask, “How long does EEG test take?”—and Dr. Miguel ensures you understand the entire process, from preparation to completion, so you feel informed and comfortable.
Whether you’re preparing for a standard EEG or need extended monitoring, Dr Miguel will guide you through the process and help you make informed decisions about your neurological care.
If you have questions and want the most accurate results, don’t hesitate to book a consultation with Dr Miguel Ley Nacher.
Because your brain health deserves expert attention.
