How is a video EEG performed?
A video EEG (electroencephalograph) monitoring is a diagnostic procedure using EEG and video recordings simultaneously in order to monitor seizure activity. A video EEG monitoring is usually performed in a hospital because it is performed for a prolonged period. The duration of the video EEG monitoring depends on the frequency of the seizures.
- Frequent episodes: outpatient procedure lasting up to eight hours of daytime monitoring, optimally when the patient is sleep deprived.
- Infrequent episodes: hospitalization for a longer period of monitoring that may last several days.
- The patient must wash their hair thoroughly and avoid using oil or hairspray.
- The patient must check with the doctor before taking any regular medications.
- The doctor may reduce or discontinue any antiepileptic drugs the patient takes in order to increase the chances of a seizure episode during the monitoring period.
- A registered EEG technician glues to the patient’s scalp, electrodes that have conductive gel on them.
- The electrodes are covered with a cap or gauze dressing.
- The electrodes are connected to an EEG unit with a cord, or a wireless system may be used.
- The technician checks to make sure the electrodes are functioning properly.
- The room will have a wall-mounted camera that continuously records the patient’s activity.
- The camera may be covered or put off when privacy is required.
- Most patients are free to move about on their own or with assistance, depending on their condition.
- A few patients may require some kind of restraint in bed. This is for their own safety, since activity during a seizure may be unpredictable, especially if antiepileptic drugs are withdrawn.
- Patients are encouraged to carry on normal daily activities including activities that are likely to trigger a seizure.
- A parent or a family member is usually present with the patient.
- The patient is provided with a buzzer that can be activated by the attendant at the onset of a seizure episode or if assistance is required.
- Certain techniques may be undertaken to induce a seizure episode during the monitoring, since its occurrence is essential for diagnosis and effective treatment. The patient will be informed prior to use of such techniques.
- The duration of video EEG monitoring will depend on seizure occurrence and adequate collection of seizure-related data.
The EEG and video recordings can be viewed simultaneously on an EEG monitor. Computer detection software is used to identify abnormal brain activity in the EEG data, greatly reducing the quantity of raw data to be studied. The registered technician analyzes and compiles the data. An epileptologist uses the findings from the video EEG monitoring to diagnose and formulate a course of treatment.
What are the limitations and risks of a video EEG?
Video EEG monitoring is a powerful diagnostic tool, but it has certain limitations:
- Errors in EEG interpretation can occur, leading to misdiagnosis.
- Certain types of partial seizures may not show activity in EEG.
- Results of the video EEG may fail to provide a conclusive diagnosis.
- Withdrawal of antiepileptic drugs or techniques to induce seizure pose potential risks to the patient that include the following: