An electroencephalogram, or EEG, is a non-invasive diagnostic study that captures a patient’s brain wave activity. Neurologists examine those wave patterns when diagnosing patients who suffer from seizures and unexplained alterations of consciousness. There are several types of EEGs and each type has its own purpose. Yet, all EEGs do the same thing. They record electrical activity from the brain.
What does an EEG Show?
Since an EEG usually shows electrographic changes during an epileptic seizure, it can help to determine whether the patient may have epilepsy or another cause for their symptoms. Psychogenic non-epileptic seizures (PNES) can mimic epilepsy. Patients with PNES can also experience loss of consciousness, muscle stiffening, and jerking movements. PNES is not epilepsy. The cause of non-epileptic seizures is psychological, and may stem from post-traumatic stress syndrome (PSTD) or a traumatic brain injury (TBI).
For many years, there was only one type of EEG study and the test would typically take 20-30 minutes. However, technological advances have improved tremendously over the course of the past two decades and today there are several types of EEGs, each with a different purpose. One of the biggest advances is in the area of ambulatory EEGs and today, an EEG can continue for many days in a row.
An EEG also helps the neurologist to determine what type of epilepsy a patient has as there are over 40 different types of epilepsies. Let’s examine two types of EEGs and when they are used.
Two Types of EEGs
A routine EEG is typically performed in a clinical setting such as a doctor’s office, hospital or clinic. This type of study is the original EEG, which lasts approximately 20-30 minutes, and is used in circumstances when a short study is deemed appropriate. However, most patients do not have a seizure within this short range of time, so doctors are now ordering a prolonged EEG study. Therefore, the patient can be evaluated over a greater length of time.
Ambulatory Video EEG
An aEEG is a prolonged study that can last from 24 hours up to a week. It can be performed in a hospital setting or within the comfort of a patient’s home. The reason behind ordering this type of EEG study would be to capture a seizure or multiple over a period of time.
Ambulatory EEG's can help doctors to determine if the events are signs of epilepsy or something else. They can use it to help determine the type of epilepsy and the area of the brain where the seizures originate.
Inpatient vs. In-Home
For safety reasons, it is important that an aEEG be performed in an inpatient setting if the patient is going through a change of medications as this might induce seizures. Medical staff is nearby to handle any emergencies. However, if a patient is not having a medication change or has a medically necessary reason for an inpatient study, having the study performed in the home can be an excellent option. In this case, the purpose of the in-home study is to record naturally occurring events. Since the hospital setting is different from a person’s normal daily routine, it can affect whether a person will have a seizure. Plus, most people want to remain in the comfort of their home, with their family and be able to do most of their typical activities.
To learn more about an in-home study and what it's like read our blog, "Preparing for an EEG Study".
Many patients who have a prolonged EEG in the hospital setting may not have an event, but as soon as they get home they have a seizure. This is frustrating for both them and their doctors. The home is where we experience our normal daily stressors. In-home Ambulatory EEG studies provide cost savings for the patients and their families as well. As we all know, the hospital is an expensive place to stay. If there is no medical reason for an inpatient stay, an in-home study can be a viable choice.
Having both these options available is important, as it allows doctors to choose the option that is best suited for their patient’s needs.