What are the indications for ambulatory Electroencephalogram (EEG)?

From the Guidelines

Ambulatory Electroencephalogram (EEG) is indicated for patients with suspected seizure disorders, paroxysmal events of unclear etiology, and characterization of seizure types in patients with known epilepsy, as well as for monitoring seizure frequency and response to antiepileptic medications 1. The primary indications for ambulatory EEG include:

• Evaluation of patients with paroxysmal events of unclear etiology
• Characterization of seizure types in patients with known epilepsy
• Assessment of response to antiepileptic medications
• Monitoring of seizure frequency
• Suspected nocturnal seizures
• Evaluation of syncope when neurological causes are suspected
• Differentiation between epileptic and non-epileptic events such as psychogenic non-epileptic seizures The advantage of ambulatory EEG over standard EEG is that it allows monitoring in the patient's natural environment, which may trigger typical events that might not occur in a clinical setting, as noted in a study on the management of patients with spontaneous intracerebral hemorrhage 1. In terms of specific patient populations, ambulatory EEG may be particularly useful for patients with impaired or fluctuating level of consciousness, as well as those with a history of seizures or suspected seizure disorders 1. It is essential to note that the use of ambulatory EEG should be guided by clinical judgment and tailored to the individual patient's needs, as the diagnostic yield and clinical utility of the test may vary depending on the specific clinical context 1.

From the Research

Indications for Ambulatory EEG

The indications for ambulatory Electroencephalogram (EEG) include:

• Differentiation between seizures and non-epileptic events 2
• Determination of the frequency of seizures and epileptiform discharges 2, 3
• Characterization of seizure type or localization 2, 4
• Potential diagnosis of epilepsy 2, 3
• Detection of interictal epileptiform discharges (IEDs) for diagnostic purposes 3
• Capturing clinical events, such as seizures or non-epileptic events 3
• Evaluation of unrecognized seizures 3
• Monitoring IEDs during treatment 3
• Classification of epilepsy syndrome 5, 4

Ambulatory EEG in Specific Patient Populations

Ambulatory EEG can be particularly useful in certain patient populations, including:

• Patients with frequent events who do not require medication taper or seizure testing for surgical localization 4
• Patients with non-epileptic events, in patients with a diagnosis of epilepsy that is not clear, and quantification of spikes and seizures to improve medical management 2
• Patients with a first single unprovoked seizure, where ambulatory EEG can help detect IEDs/seizures and predict seizure recurrence 6

Advantages of Ambulatory EEG

The advantages of ambulatory EEG include:

• Cost-effectiveness compared to inpatient video-EEG monitoring 2
• Convenience and ability to record EEG in the patient's natural environment 5, 2
• Ability to capture EEG activity during all sleep stages and transitional states 4
• Superior sampling compared to standard EEG recordings 4