Electroencephalogram(EEG)

Overview: 

An electroencephalogram records the brain's activity and detects abnormalities in the brain waves. This makes it a very vital tool for diagnosing multiple neurological disorders, especially epilepsy, by understanding the workings of the brain more clearly. 

Electroencephalogram is a non-invasive technique. The test records the electrical activity in the brain through the brain's neurons with the help of metal discs called electrodes. The electrodes are attached to both sides of the scalp and record the electrical impulses the brain cells send out. The recordings are in the form of curved or wavy lines, which have different frequencies depending on the state of the brain. These curved lines reflect cognitive processes like memory, sleep, and attention. 

What Medical Conditions Does An Electroencephalogram Detect: 

• Brain tumors. 
• Brain damage caused due to head injury and concussion. 
• Brain dysfunction. 
• Sleep disorders like sleep apnea. 
• Inflammation of the brain. 
• Stroke. 
• Creutzfeldt-Jakob disease. 
• Dementia. 

Applications Of An Encephalogram: 

• The placement of electrodes on the scalp helps identify electrical signals accurately and assists in indicating seizures. This is important in the treatment of epilepsy. 
• EEG plays a significant role in studying sleep and circadian rhythms by checking brain activity during different sleep stages. This also helps determine the neurons' activity during sleep and analyze the sleep patterns. The polysomnography study uses EEG to observe brain activity during sleep and helps diagnose multiple sleep disorders. 
• EEG is used in neurological research to check the workings of the brain while the person performs various mental tasks. This helps researchers get valuable insights into human cognitive processes. 
• EEG is applied in Neurofeedback, also known as EEG biofeedback, and has shown significant results in conditions like ADHD, anxiety, and depression by helping patients learn to self-regulate their brain function.  

Types Of Encephalograms

• Routine EEG: This routine test is conducted within 30 to 40 minutes. The person is asked to open and shut their eyes repeatedly, inhale and exhale deeply, and use a flashlight to check brain activity. 
• Sleep EEG or sleep-deprived EEG: This test is done when a person is asleep and is conducted when the routine EEG fails to provide sufficient information for sleep disorders. Some individuals may be asked to stay awake the night before so that they fall asleep for the test. 
• Ambulatory EEG: This test records the brain activity throughout the day and at night for a few days through a small portable recorder attached to a person's clothes. Care should be taken so that the device should not get wet. 
• Video telemetry: This test is also called video EEG. The procedure involves filming the person while the brain activity is being recorded to get additional information about the brain's activity. The brain signals and the recording are done on a computer by trained technicians. 
• Invasive EEG-telemetry: This test is used to determine if surgery is a viable option for people with complex epilepsy. It includes surgical intervention to place electrodes directly on the brain to detect the exact location of seizures. 

The Procedure

•  Before the procedure, the person is asked to take their usual medications, wash their hair the night before, and avoid using hair products.  
• The person is advised to avoid sleeping if sleeping is required during the procedure. 
• A technician measures the head of the person, and markings are done on the scalp to place the electrodes. 
• The electrodes are stuck to the scalp using an adhesive or a cap, and they are connected with wires to a device that records the brain waves on a computer. 
• Before recording begins, the impedance of each electrode is checked to ensure optimal signal quality. 
• The procedure takes approximately 30 to 40 minutes, and the person is asked to lie down in a comfortable position. Depending on the type of electroencephalogram, the person is either asked to open and close their eyes, breathe deeply, look at a flashing light, or look at a picture. 
• The person may be video recorded depending on the type of test. 
• After the test, the technician detaches the electrodes. If the person is given a sedative, returning to normalcy takes a little longer. 
• Doctors analyze the results and schedule an appointment to discuss them with the person. 

Challenges and Limitations

The EEG procedure is relatively painless and safe as no electricity enters the body. However, there are a few disadvantages that people may experience.  

• Messy hair 
• Fatigue 
• Dizziness 
• Tingling in the lips and fingers 
• Rash at the place where electrodes are put. 
• Risk of seizure if the person has epilepsy. 
• The signals that are recorded result from many neurons, making it challenging to locate the exact origin of the signals. 
• Muscle activity, eye movement, and certain distractions from the environment, like bright lights, make it challenging to obtain accurate brain signals. 
• The procedure has limited spatial resolution compared to other neuroimaging techniques due to the constraints of the scalp and skull tissues. This limitation hinders providing the actual location of the brain activity.  

Conclusion

An EEG measures the brain waves and helps detect any abnormality in the brain activity safely and painlessly. The results obtained from this procedure help in the detection of conditions like epilepsy, a brain tumor, or a stroke. It is important to note that certain people with epilepsy stand the chance of a seizure during the procedure. Still, overall, the method has proved extremely helpful in aiding people dealing with neurological disorders and maintaining quality of life.