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Stanford Health Care

Electroencephalogram (EEG)

Our Approach to Electroencephalograms (EEGs)

An electroencephalogram (EEG) is a safe, effective test that records and measures your brain’s electrical activity. Our neurology specialists use EEG testing to diagnose, monitor, and plan treatment for seizures, brain tumors, head injuries, strokes, and other brain conditions.

Our skilled neurologists, neurosurgeons, and EEG technicians have advanced training and experience in the newest EEG technologies. Combining these leading-edge tools with our expertise in reading EEGs, we deliver detailed results that guide precise treatment planning for personalized care.

At Stanford Health Care, we offer comprehensive EEG testing that explores all the possibilities to uncover the underlying causes of brain disorders.

What We Offer You for EEG Testing

  • Expert team of neurologists and EEG technicians with years of experience conducting and reading all types of EEGs to evaluate and diagnose a wide range of brain conditions. 
  • The latest EEG technologies for assessing brain activity patterns, identifying changes, and mapping locations for epilepsy, tumors, brain injuries, and other disorders.
  • Inpatient intracranial video EEG in our Epilepsy Monitoring Unit (EMU) for intensive 24/7 monitoring and in-depth testing for people with drug-resistant epilepsy. 
  • Comprehensive EEG testing in our Neurodiagnostic Labs, with short-term, long-term, sleep, and other types of EEG to diagnose and monitor neurological conditions.

What Is An Electroencephalogram?

About Electroencephalogram

An electroencephalogram (EEG) records and measures your brain’s electrical activity, including brain wave patterns and any unusual changes. Brain cells communicate with each other by sending electrical signals, even when you’re asleep. On an EEG, this activity looks like wavy lines.

For most types of EEG, our technicians attach electrodes (small, metal sensors) to your scalp using washable glue. Or you may wear a cap with embedded electrodes. These EEGs usually take about one hour to several hours. In some cases, our neurosurgeons perform surgery to place electrodes in or on the brain to record electrical activity for a longer period of time.

The electrodes sense the electrical impulses as they travel between brain cells. The electrodes send information about the impulses through wires connected to the EEG equipment. The equipment records the information as lines that show your brain wave patterns.

The brain produces specific wave patterns when you’re asleep or awake. Changes in these patterns can occur with seizures, sleep disorders, brain injuries, and other brain conditions.

Interpretation of the EEG
An EEG might be normal or it may reveal abnormalities suggestive of epilepsy or a condition that mimics epilepsy. The epilepsy patterns are divided into interictal, meaning between seizures, or ictal, meaning during a seizure. Interictal discharges last less than one-fifth of a second and are not perceived by the person having the EEG, but they commonly come from the region where seizures originate.

Video EEG monitoring attempts to capture the location of abnormal ictal discharges at the start of a seizure. Recording several seizures may be necessary to know whether a particular part of the brain is consistently the site of seizure origin. In rare cases, seizures deep in the brain may not be detected by EEG electrodes on the scalp. If a test fails to record spikes, seizures, or clinical events, it is inconclusive, because it cannot rule out seizures occurring at other times.

Make An Appointment

To schedule an appointment, please call 650-723-6469.