The test can also be used to monitor activity during brain surgery. EEG is usually painless and very safe. If an EEG does not produce any abnormalities, stimuli such as strobe lights, or rapid breathing may be added to help induce any abnormalities.
The technician performing the EEG is trained to safely manage any situation that might occur. Hyperventilation is also commonly induced during an EEG to produce abnormalities. Some people may not be able to hyperventilate safely, such as people with a history of stroke , asthma , or sickle cell anemia.
The person responsible for interpreting your EEG will take these movements into account. They include:. Other factors that can influence your EEG reading include:. An EEG measures the electrical impulses in your brain by using several electrodes attached to your scalp. An electrode is a conductor through which an electric current enters or leaves. The electrodes transfer information from your brain to a machine that measures and records the data.
The test usually takes roughly 30 to 60 minutes to complete and involves the following steps:. In some instances, a person may undergo a hour EEG. These EEGs use video to capture seizure activity. The EEG may show abnormalities even if the seizure does not occur during the test. However, it does not always show past abnormalities related to a seizure.
You can continue with your regular routine. However, if you were given a sedative, the medication will remain in your system for a little while. This means that you may need to have someone with you to take you home after the test.
A neurologist someone who specializes in nervous system disorders interprets the recordings from the EEG and then sends the results to your doctor. Your doctor may schedule an appointment to go over the test results with you. Electrical activity in the brain appears in an EEG as a pattern of waves.
On the other hand, a normal EEG doesn't rule out epilepsy either. Sometimes, a person with epilepsy will only display abnormal brain waves during a seizure. Your hair must be thoroughly clean, but most importantly dry. A number of electrodes are applied to your scalp generally between 8 and 23, depending on the condition under investigation.
A gel may be applied to help the electrodes to stick firmly in place and improve recordings. You will need to lie quietly to avoid any electrical interference from muscle contractions.
Sometimes, you may be asked by the doctor to open and close your eyes and to breathe heavily. Lights may be flashed before your eyes. An EEG usually takes from 30 to 60 minutes to complete. Sometimes, a sleep recording is also required. If the patient is a baby or young child, it helps if the parents delay the child's nap until the time of the EEG. Sedatives medications to help sleep may be needed if sleep won't come naturally during the test.
Some EEG testing centres may record a video of your tests to help with diagnosis. Once the test is complete, the electrodes are removed and you are allowed to get up.
The results need to be analysed at a later stage by a neurologist a doctor who specialises in brain disorders. Generally, if there is no abnormality to the brain's electrical activity, the pattern of 'peaks and valleys' charted by the EEG should be fairly regular.
If excited, the pattern will show considerable variation, and any departure from the regular pattern can indicate abnormalities. EEG is a safe test with no side effects. However, a person with epilepsy may experience a seizure, triggered by the various stimuli used in the procedure, including the flashing lights. This is not seen as a 'complication' by medical staff, because a seizure during an EEG can greatly help in diagnosis.
EEG is a safe procedure. Be advised by your doctor, but generally, there are no special instructions for after-care. However, you will need to wash your hair thoroughly to remove all traces of gel and other fluids. The EEG technologist can't interpret the test results on the spot. The EEG recording must be analysed by a neurologist, who then sends the results to your doctor.
The electrical signals from the brain are converted into wavy lines on a computer screen. Your child will be asked to lie still because movement can change the results. If the goal of the EEG is to mimic or cause the problem your child is having like seizures , he or she may be asked to look at a bright flickering light or breathe a certain way. The health care provider performing the EEG will know your child's medical history and will be ready for any issues that could come up during the test.
Most EEGs take about an hour. If your child needs to sleep during it, the test will take longer. You might be able to stay in the room with your child, or you can step outside to a waiting area. An EEG isn't uncomfortable, and patients do not feel any shocks on the scalp or elsewhere.
Still, having electrodes pasted to the scalp can be a little stressful for kids, as can lying still during the test. A neurologist a doctor trained in nervous system disorders will read and interpret the results. Though EEGs vary in complexity and duration, results usually are available in a few days. EEGs are very safe. If your child has a seizure disorder, your doctor might want to stimulate and record a seizure during the EEG.
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