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nerve cells of the brain have electrical activity, and give
off electrical signals. With an eeg, the potential difference
between pairs of electrodes is amplified, and displayed for
the physician either on a computer screen, or more traditionally,
on moving paper. Electrodes are placed on the scalp.
The electrical patterns can be used to locate or diagnose the
source of seizure activity, metabolic or structural lesions
within the brain, and can also be used to assure that the brain
is adequately sedated, as in the case of pentobarbital coma
being used to treat brain swelling, or when barbiturates are
used to intentionally suppress brain activity during aneurysm
clipping and carotid endarterectomy.. Certain maneuvers
can be used to provoke abnormalities during an eeg, such as
hyperventilation, sleep deprivation, and photic stimulation
(strobe lights).
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