How Can an EEG Help Diagnose Angelman Syndrome?

Emily Malcolm, PhD avatar

by Emily Malcolm, PhD |

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MRI for Angelman syndrome

An electroencephalogram (EEG) is a test that can be used to diagnose Angelman syndrome and monitor progression of the disease.

What is an EEG?

An EEG is a test that measures electrical activity in the brain using small sensors that are placed on the head for the duration of the test. The sensors consist of 15 to 30 small metal disks, which may be adhered to the head or attached to a cap that is placed over the head.

The test takes about 30 minutes to an hour to complete, but putting on and taking off individual sensors also can take about 30 minutes, so it may be wise to set aside a total of two hours for the whole procedure.

During the test, patients usually are asked to sit or lie down with their eyes closed. They may be asked to read, play, or sleep to get a measure of brain activity in response to different stimuli.

How to prepare for an EEG?

Talk with your child’s doctor to find out whether there are any medications that should not be taken on the day of the test. Patients should avoid caffeine prior to an EEG.

Wash hair the night before the test, but don’t use any hair gel, cream, or styling spray.

What do the results mean?

The electrical activity of the brain of patients with Angelman syndrome has several distinctive patterns that are recognizable by physicians. These patterns are distinctive from the patterns caused by brain tumors, brain damage, or epileptic seizures not caused by Angelman syndrome.

There usually are no differences in these patterns between patients who have Angelman syndrome with seizures, and those who have the disorder without seizures.

What happens after the EEG?

A physician will discuss results of the EEG with the patient, and whether changes in medication or therapy are necessary.

There usually are no aftereffects of an EEG, though some patients may feel tired afterward.


Last updated: Oct. 2, 2019


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