What is Electroencephalogram (EEG)?
Electroencephalogram (EEG) is a painless diagnostic procedure that records electrical signals of the brain to assess the brain’s electrical activity that is recorded and displayed on a monitor in a pattern of wavy lines. EEG provides an insight into the function of the brain and helps in differentiating various electrical signals produced by the brain when in a diseased condition.
Anatomy of the Brain
The brain is a major organ formed by nervous tissue that along with the spinal cord forms the central nervous system or CNS. The 3 major parts of the brain are the cerebrum which controls emotions, memory, movement, and problem-solving skills; the cerebellum helps in maintaining balance and fine motor skills, and the brain stem controls the reflexes and automatic functions like breathing and heart rate. Nerve impulses produced from the brain are transmitted to different parts of the body through the nervous system.
Indications of Electroencephalogram (EEG)
An electroencephalogram is mainly indicated to diagnose abnormal electrical activity of the brain, which helps to detect conditions such as:
- Epilepsy
- Sleep disorders
- Dementia
- Head injuries
- Brain infection
- Tumor
- Alzheimer disease
- Confusion
- Sleep apnea
- Encephalopathy
- Stroke
- Brain hemorrhage
Types of Electroencephalogram
Some of the most common types of electroencephalogram include:
- Routine EEG: This procedure will take about 20-30 minutes during which your technician will monitor the stimuli like breathing or response to flashing lights.
- Prolonged EEG: This procedure will take about 1 hour and 15 minutes. It provides more information and can help in the diagnosis and management of seizer disorders.
- Ambulatory EEG: This is a painless diagnostic method of recording electrical signals produced by the brain over 24-96 hours in natural settings where the recorder is tied to your waist.
- Sleep EEG: This test is usually performed while you are sleeping to detect any sleep disorder.
- Video EEG: Your technician will take a video recording during the EEG test to correlate physical signs and symptoms with abnormal brain activity.
Preparation for Electroencephalogram
Preparation for electroencephalogram includes:
- Wash and dry your hair the day before the test.
- Avoid using any gel, spray, or hair products before coming for the test.
- Avoid intake of caffeine or any food items 8- 12 hours before the test
- Tie your hair loosely and do not wear any hair clips before the test.
- Do not stop taking your medications unless told by your doctor to do so.
- Wear loose comfortable clothes.
Procedure of Electroencephalogram
An electroencephalogram is usually done on an outpatient basis or as part of your hospital stay. The procedure usually includes:
- Your doctor will instruct you to lie on a bed or a reclining chair.
- The technician will measure your head size and mark the areas to place the electrodes
- The electrodes are placed on the scalp and held in place using adhesive and, in some cases, a plastic cap is used.
- The electrodes are connected with wires to an instrument that amplifies the brain waves and records them.
- Your technician will instruct you to close your eyes and stay still during the test.
- During the procedure, your technician may check for alteration in your brain's electrical activity to certain stimuli such as flashing lights.
- Depending on the type of EEG, the procedure may last from 20-30 minutes to several hours, or in the case of an ambulatory EEG, you will be allowed to go home and continue with your usual activities while wearing the portable EEG recorder for 1-3 days.
Post-procedure Care for Electroencephalogram
After the test, the electrodes will be removed and your scalp will be washed with warm water. As no sedative is provided, resting after the procedure is not required. You can continue your normal routine immediately after the test.