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What is an Electroencephalogram (EEG)?
An Electroencephalogram, also called an EEG, is a record of the electrical activity of the brain. The brain cells, called neurons, communicate with one another by the generation of small electrical discharges. These electrical impulses are recorded by placing leads on different parts of the head, and plotting the waves on paper. It is a diagnostic procedure to detect any abnormality of function or disorder of the brain.
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How to prepare for an EEG?
No special preparation is necessary except that the hair has to be cleaned or shampooed. The hair should be dry and no oil or dye should be applied on the day of the test.
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What happens during the EEG?
It is a painless procedure in which small flat metal disks are attached to the scalp. Sometimes small wires may also be placed through the nose to the back of the throat. The disks have electrodes, which are connected to a machine that records the electrical impulses of the brain and gives a tracing on paper. Any abnormalities of the brain’s electrical activity can be diagnosed easily by reading the paper tracing. The test usually takes an hour. Small children may require medicine to put them to sleep for the test.
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Why is it done?
It helps to diagnose and assess brain disorders. It is useful in the diagnosis of brain tumours, epilepsy, sleep disorders, and some metabolic abnormalities. It is one of the investigations for certifying brain death.
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Are there any limitations of this procedure?
There are no obvious risks. It does not measure the intelligence or read the mind. Sometimes the EEG may not show any abnormality in the early stages of a problem.
