Electroencephalogram (EEG) for the Diagnosis of Angelman Syndrome

Angelman syndrome is a rare disease characterized by delayed motor and mental development. Symptoms can be apparent starting at a young age, but diagnosing this disease is often challenging.

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

What is an EEG?

An EEG 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 itself typically takes between 30 minutes and an hour to complete. But placing and removing each sensor also takes about 30 minutes, so it is advisable to set aside a total of two hours for the whole procedure.

During the test, patients are usually 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.

For those who need to be monitored during sleep, a sedative may be administered, or patients may be asked not to nap prior to the test so they might find it easier to fall asleep during the EEG.

How does an EEG help diagnose Angelman syndrome?

Electrical activity in the brain of people with Angelman syndrome has several distinctive patterns that are recognizable to physicians. These patterns are different from those caused by brain tumors, brain damage, or epileptic seizures not due to Angelman syndrome.

There usually are no differences in these patterns between Angelman patients with seizures and those without seizures.

Following the test, the physician will explain test results to the patient and/or family members, and any changes to medication or other therapies that may be required.


Last updated: Oct. 03, 2019


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