Everything you Need to Know About EEG Test: Use, Procedure, and Results

Electroencephalogram (EEG) is a neurological test used to analyze the electrical activity of your brain. EEG test procedure involves attaching adhesive electrodes to your scalp that measure your brain wave patterns to help diagnose conditions such as seizures, epilepsy, dementia, and sleep disorders, among others. This diagnostic tool detects the presence of electrical activity in the brain that indicates communication between cells as well. In this blog post, we explore everything you need to know about EEG test – from its usefulness, procedure to interpretation of results.

Why Would a Neurologist Order an EEG?

EEG is a diagnostic tool used in neurology to detect and diagnose a wide range of neurological conditions. A neurologist may order an EEG test for various reasons including:

  1. Seizures – Seizures are a result of abnormal electrical activity in the brain, and an EEG test helps in identifying the location and type of seizures in an individual.

  2. Epilepsy – An EEG test helps in the diagnosis and treatment of epilepsy, a neurological disorder characterized by recurrent seizures.

  3. Sleep disorders – EEG is useful in diagnosing and treating sleep disorders like sleep apnea, narcolepsy, and disturbed sleep.

  4. Brain injuries – In case of a head injury, EEG is used to identify the damage done to the brain.

  5. Neurodegenerative diseases – EEG helps neurologists in identifying abnormalities associated with Alzheimer’s disease, Parkinson’s disease, and other neurodegenerative disorders.

What is EEG Test Used to Diagnose?

EEG is used to diagnose a range of neurological conditions. The test measures electrical activity in the brain to detect issues like:

  1. Seizure disorders: EEG can identify the type of seizures and their location, allowing doctors to adjust medications and treatment plans accordingly.

  2. Sleep disorders: EEG helps identify sleep patterns and disruptions, including sleep apnea, narcolepsy, and restless leg syndrome.

  3. Brain tumors: EEG can detect abnormal electrical activity caused by tumors, allowing prompt diagnosis and treatment.

  4. Brain damage or injury: EEG can help identify the type and location of any damage or injury to the brain.

  5. Neurological conditions: EEG can identify abnormalities in the brain that may be associated with dementia, autism, and other neurological conditions.

EEG Procedure

An EEG typically takes thirty minutes to an hour to complete. The procedure involves the following steps:

  1. The patient sits or reclines in a comfortable chair or bed.

  2. The technician applies an electrode paste that makes a smooth conductive surface, and attaches electrodes to the patient’s scalp.

  3. The electrodes are connected to an electroencephalograph that amplifies and records the electrical activity of the brain.

  4. As the EEG is recording the patterns, the technician may give instructions, such as opening and closing eyes or breathing deeply.

  5. The recording is complete and removed. The technician may need to clean the paste off the scalp.

  6. The data collected is sent to a specialist for interpretation.

Abnormal EEG Results

An EEG may be normal or abnormal. Abnormal results indicate that the electrical activity in the brain is out of the normal range, possibly due to an underlying condition.

10 conditions diagnosed with an EEG include:

  1. Epilepsy
  2. Sleep disorders
  3. Head injuries
  4. Tumors
  5. Brain infections
  6. Encephalitis
  7. Stroke
  8. Alzheimer’s disease
  9. Parkinson’s disease
  10. Autism

What Happens if EEG is Abnormal?

An abnormal EEG result means that there is an issue with the patient’s brain activity. The results reveal the type, location, and severity of the issue. The patient’s doctor or a neurologist usually interprets the results and may recommend additional tests or treatment.

How Long is an EEG Test for Seizures?

An EEG test for seizures usually takes 45-60 minutes to complete. The test measures the electrical activity in your brain to identify the type and location of the seizures.

Which is Better EEG or MRI?

Both EEG and MRI are diagnostic tools used in neurology to identify brain-related conditions. However, they are different and used in different situations. EEG measures the electrical activity of the brain while MRI captures images and is used to detect abnormalities in the physical structure of the brain. It all depends on the condition being diagnosed or the symptoms experienced by the patient.

What Can an EEG Show That an MRI Cannot?

EEG and MRI have their unique purposes, and neither is superior to the other. An EEG can detect rapid, intermittent changes in brain activity that MRI may not capture. On the other hand, MRI can identify structural abnormalities that may be missed on EEG.

How Long Do EEG Results Take?

The time it takes to get EEG test results depends on the healthcare provider and type of facility. Some providers can provide results within a week, while others may take a couple of weeks. It’s healthy to maintain close communication with your healthcare provider to determine how long it will take to receive results.


An EEG is a diagnostic test that measures brain wave patterns and detects the location and type of seizures and abnormalities in the brain’s electrical activity. The procedure is painless and straightforward, and the results guide medical treatment and management. Understanding the significance of the EEG test, including procedure and interpretation, are crucial to receiving proper medical care.