Electroencephalograph (EEG)

EEG is widely used to diagnose conditions affecting brain activity, including epilepsy, seizures, sleep disorders, infections, brain tumors, and brain damage. It involves placing electrodes on the scalp, which pick up electrical signals from neurons and record them as wave patterns. These patterns reveal abnormalities in brain function that can guide diagnosis and treatment.

Before performing an EEG test, certain factors need to be considered. There are no strict reasons to avoid an EEG. However, placing electrodes may be hard if you have had brain surgery (craniotomy), skull damage, or open wounds on your head. EEG should be done only after the doctor takes a detailed history, especially if seizures or epilepsy are suspected. Certain procedures during an EEG, like hyperventilation (deep breathing), should be avoided if you have some health issues. These include a history of stroke, heart attack, organ transplants, lung problems (like asthma or acute respiratory distress), Moyamoya disease, or sickle cell anemia. Your doctor will decide whether it is safe to perform the test and whether any modifications are needed.

For EEG test preparation, wash your hair the night before the test. Avoid using products like conditioner, hairspray, or gel. Avoid consuming caffeine-containing foods or drinks for at least 8 to 12 hours before the test. Informed consent is required. Inform your doctor about all medications or supplements you take, as they may affect the test results. You need to relax, keep your eyes open and closed, or respond to stimuli like flashing lights or deep breathing.

Interpretation of biopsy results requires expert advice. Self-medication based on biopsy reports is discouraged. Always discuss findings and next steps with your healthcare provider.

Disclaimer: You must visit your nearest Tata 1mg-partnered lab for radiology tests.

How to Prepare for an EEG?

• Wash hair thoroughly the night before or on the day of the test, without hair products.
• Avoid caffeine for at least 8 hours before testing.
• Continue medications unless advised otherwise.
• Inform technician of any allergies or skin sensitivities.
• Wear comfortable, loose clothing without metal.
• Arrive on time for the appointment.

How is the EEG Performed?

• Electrodes are attached to specific scalp locations using a mild abrasive cream, adhesive gel, or a cap.
• The patient relaxes in a quiet, dimly lit room, often in a reclining chair or bed.
• Electrical signals from the brain are recorded over a few minutes.
• Patients may be asked to open/close their eyes, breathe deeply, or respond to light flashes to provoke changes in brain activity.
• Video monitoring may be used alongside EEG for clinical correlation.

How Does EEG Work?

EEG measures electrical impulses produced by brain cells (neurons) to reveal normal or abnormal brain wave patterns.

Who Should Avoid or Take Precautions Before an EEG?

• Inform the technician if pregnant or breastfeeding
• Allergies to adhesives should be reported
• Recent sedatives may affect results
• Sleep deprivation EEG requires prior guidance

What to Expect During an EEG?

• No pain, occasional mild discomfort from electrode placement
• Instructions to relax but remain still
• Test duration may take from a few minutes to several hours, depending on the type.

What to Expect After an EEG?

• No restrictions; activities may resume immediately
• Hair may require washing to remove adhesives
• Follow up with the healthcare provider for interpreting results

Is EEG a Safe Procedure?

Yes, the EEG test procedure is generally very safe and painless. It records your brain's electrical activity using small electrodes placed on your scalp. There is no electric current passing through your brain. Some people may feel slight discomfort from the electrodes or mild tingling during deep-breathing tests. If you have epilepsy, flashing lights or deep breathing used during an EEG might rarely trigger a seizure, but trained staff will manage it safely.

Is It Safe to Have an EEG if You Are Pregnant?

EEG is safe for most people, including pregnant women, as it does not use radiation. However, always inform your healthcare provider if you are pregnant. Some activation procedures, like hyperventilation, may be avoided in certain medical conditions. Your doctor will decide the safest approach based on your health.

What Are the Risks of an EEG?

• No significant risks or side effects; mild skin irritation possible
• Results can be influenced by medications or movement

What Are the Limitations of an EEG?

• Does not provide structural brain images, only electrical activity data

How Are the Results Used?

• To confirm epilepsy or seizure type
• Guide treatment in neurological disorders
• Assist in evaluating brain function post-injury