EEG Test

Your brain generates electrical signals continuously, even during sleep. Doctors use EEG test, or electroencephalography, to record these spontaneous electrical activities in your brain without invasive procedures. These patterns mean much more than simple recordings - they show frequencies between 1 and 30 Hz and amplitudes from 20 to 100 μV. Your brain creates distinct EEG patterns that doctors can interpret based on how awake you are. 

EEG proves especially valuable to evaluate patients who might have seizures or epilepsy. Additionally, this versatile tool helps doctors assess sleep disorders and determine brain activity in coma patients. 

What is an EEG Test?

An EEG test captures the brain cells' electrical activity. Small, flat metal discs called electrodes attach to the scalp in this painless procedure. The electrodes detect electrical impulses as brain cells communicate. These signals flow through wires to a computer that shows them as wavy lines with peaks and valleys. The test creates a visual map of brain waves that doctors use to spot unusual patterns.

When Should You Get the EEG (Electroencephalogram) Test? 

You might need an EEG test if you face these issues:

• Seizures or suspected epilepsy
• Unexplained memory loss
• Sudden confusion or fainting
• Most important changes in behaviour

Your doctor might suggest this test to track brain activity in conditions like Alzheimer's disease, brain infections, tumours, traumatic brain injuries, or stroke.

Why Do I Need an EEG Test?

Diagnosing epilepsy and monitoring seizure activity stand as the main goals of an EEG. This versatile test helps doctors:

• Spot brain injuries, infections, or tumours
• Diagnose sleep disorders like narcolepsy
• Track patients in a coma
• Check brain function during surgery
• Review psychiatric disorders
• Track cognitive decline

The test helps determine if treatments work and can identify non-convulsive seizures that might stay hidden otherwise.

Procedure for EEG Test

This noninvasive procedure is simple. The medical staff will ask you to sit on a chair or lie down on a table. They will clean your scalp and temple area. The technician places small metal discs called electrodes on the scalp using a conductive gel and connects them to an EEG machine. You will be asked to relax, remain still, or perform certain movements (open and close the eyes, breathe deeply, or look at flashing lights). The technician records the brain's electrical activities. After that they remove the electrodes and clean the area.

How to Prepare for the EEG (Electroencephalogram) test?

Your EEG test preparation requires some simple steps. These are:

• You should wash your hair the night before but skip conditioners, hair creams, sprays or styling gels
• Stay away from caffeine and stimulants at least 12 hours before the test
• Keep taking your prescribed medications unless your doctor tells you otherwise
• Let your doctor know about all your medications, including over-the-counter ones
• Some tests need sleep restriction - adults should sleep only 4-5 hours, while children need 5-7 hours

Values of EEG scan Results

Your brain produces five main types of waves, each with distinct meanings:

• Delta waves (0.5-4 Hz): These waves are normal during deep sleep. If they appear when you are awake they might indicate brain dysfunction 
• Theta waves (4-8 Hz): You will see these during drowsiness or light sleep 
• Alpha waves (8-13 Hz): These show up when you are relaxed with your eyes closed 
• Beta waves (13-30 Hz): Your brain produces these during active thinking 
• Gamma waves (30+ Hz): These waves reflect complex cognitive tasks

What Abnormal Results Mean

Your EEG might show unusual patterns that could point to:

• Seizure disorders or epilepsy, which appear as rapid spiking waves
• Brain tumours or strokes that typically show very slow waves
• Unusual bleeding in your brain
• Head injuries or brain infections
• Sleep disorders like narcolepsy
• Metabolic diseases linked to kidney or liver problems

Note that EEG results are just one part of your complete diagnostic picture. Your doctor will look at them along with your symptoms and other test results.

Conclusion

EEG is a painless method to spot issues like epilepsy, sleep disorders, and other neurological conditions without surgery or invasive procedures. Doctors learn significant clues about your neurological health by analysing your brain waves – delta, theta, alpha, beta, or gamma. Each pattern tells a unique story about your brain's activity.

Modern brain imaging techniques continue to advance, yet EEG remains vital because of its affordability, accessibility, and live monitoring capabilities. This test often captures electrical signals that other methods might miss. This simple test provides information that could unlock answers about your brain health and guide your treatment path.

FAQs

1. What happens if an EEG test is positive?

A positive or abnormal EEG shows unusual electrical patterns in your brain. These patterns might point to:

• Seizure disorders or epilepsy 
• Brain tumours 
• Strokes 
• Abnormal bleeding inside the brain
• Sleep disorders like narcolepsy

2. What happens if an EEG test is negative?

A negative or normal EEG means your brain activity looks normal. This doesn't automatically rule out conditions like epilepsy. Someone with epilepsy might show abnormal brain waves only during an actual seizure.

3. How to prepare for an EEG test?

You should wash your hair really well the night before, but skip conditioners or styling products. Stay away from caffeine for at least 6-8 hours before the test. Keep taking your prescribed medications unless your doctor says otherwise. Sleep EEGs need special preparation, so follow your doctor's instructions about reduced sleep.

4. Is an EEG test painful?

No you won't feel any pain during an EEG test. You might feel slight discomfort when the electrodes are placed.

5. Is it better to have a high or a low EEG test?

Neither high nor low readings are better. What matters is having normal wave patterns that match your age and state of consciousness.

6. What is a normal EEG test level?

A "normal" EEG displays typical brain wave patterns with appropriate frequencies. Alpha waves (8-12 Hz) appear during relaxation, beta waves (13-30 Hz) show up when you are awake and alert, theta waves (4-7 Hz) emerge during light sleep, and delta waves (0.5-3 Hz) occur in deep sleep. These patterns shift naturally based on your consciousness level and mental activity. Your brain's electrical activity should fall within expected ranges for your age to be considered "normal."

7. What happens if EEG is abnormal?

An abnormal EEG shows unusual electrical activity in your brain. This could indicate conditions like epilepsy, seizures, brain injuries, or sleep disorders. Children with autism spectrum disorder who show abnormal EEG results tend to face more challenges with executive functioning and social relationships. The results don't automatically confirm epilepsy - you might need additional tests.

8. What not to do before an EEG test?

Stay away from caffeine at least 8-12 hours before the test. Your hair should be free of products like gels, sprays, or oils. Get normal sleep unless your doctor asks for sleep-deprivation testing. Of course, you should skip gum and crunchy foods before the test.

9. How long does an EEG test take?

Standard EEG tests run for 20-40 minutes. The whole appointment takes about an hour to include preparation and cleanup time. Sleep-deprived EEGs might last 1-2 hours.

10. What should I avoid before an EEG?

Beyond caffeine, stay away from stimulants like nicotine. Your hair must be free from conditioners or styling products. Physical activities that make you sweat should be avoided. Keep taking your prescribed medications unless your doctor tells you otherwise.