How to prepare for EEG in an outpatient setting.

The EEG measures brain wave activity and is often used to investigate a patient's history of seizures.

The “interictal EEG” describes abnormalities seen in patients between seizures. It is well known that even when patients appear well and have no outward manifestation of seizures, the brain waves can show abnormalities suggestive of a seizure tendency or risk.

The “ictal EEG” describes the EEG changes that are seen during a seizure. This finding is not commonly seen during the routine outpatient EEG recordings. The capture of a seizure confirms the diagnosis of epilepsy and helps in identifying the specific epilepsy syndrome or disorder the patient has.

Video EEG Monitoring (Non-Invasive)

Long-term video EEG monitoring is used to either confirm the diagnosis of epilepsy, or confirm the first part of a series in an investigation for the possible role of epilepsy surgery for the treatment of epilepsy.

Patients are usually admitted for five to seven days to the Epilepsy Monitoring Unit (EMU) with placement of scalp EEG electrodes and frequent Sphenoidal Electrodes.

The goal of video EEG monitoring is to record the patient’s typical seizures. For this reason, the anticonvulsant medications are usually tapered down and frequently discontinued within the first few days of the patient’s stay in the EMU. The seizures are captured with video and EEG recordings and upon the completion of the evaluation the patient is reloaded on their anticonvulsant medications.

Sphenoidal Electrodes

Sphenoidal Electrodes are used to record activity from near the base of the brain, called the temporal lobe, and orbital frontal area.

The electrodes are placed by a physician at the patient’s bedside. The patients are sedated for the procedure and the electrodes are placed with the aid of a needle into the region of the cheeks. The needle is removed and a thin wire is left in place and taped to the skin. The electrodes are easily removed upon completion of the evaluation.

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