Electroencephalography

Electroencephalography, also referred to as an EEG test is a test that detects abnormalities in your brain waves, or in the electrical activity of your brain. An EEG should always be recorded by a qualified individual. This may either be an HPCSA registered Clinical Neurophysiologist or a HPCSA registered EEG Technician.

It is important that you know whether the person performing the EEG is registered with the HPCSA. 

An electroencephalogram (EEG) is a test that measures electrical activity in the brain. Brain cells – or neurons- communicate via small electrical impulses that will be recorded as wavy lines on a computer screen. These signals happen all the time - even while you are sleeping.

It can be done in several settings:

Routine electroencephalography (EEG): 

A routine EEG can be performed either in the hospital or as an outpatient test. 

EEGs are non-invasive and non-painful test, and your appointment should take between 60 – 90 min. It can sometimes take a little longer for small children that may not be as co-operative as an adult.

A routine EEG can be done while you or awake or your doctor may ask for a sleep EEG 

Before the test, you’ll need to make sure your hair is clean and doesn’t have any hair sprays, oils or gels in it. These products can interfere with the function of the electrodes.

• How is an EEG done

During an EEG you will either be asked to lay on a bed or comfortably recline on a chair while small, metal discs called electrodes are pasted onto your scalp. These are small metal disks with thin wires. 

You will be asked to open or close your eyes at times and may be asked to do deep breathing exercise for three to five minutes. This may make you tired of feel lightheaded but is not dangerous.

There may also be a bright light that will be flashed in front of your face during period with your eyes open or closed. You may feel dizzy of see bright colours during the flashes.

It is important to try and remain relaxed and sometime even try and fall off to sleep.

• Some reasons why your doctor may refer you for an EEG

EEG is the only method of evaluation of brain function and assessment of degree of functional impairment. Impaired brain function may be due to structural abnormalities or brain tumours, traumatic injuries such as brain damage from a head injury, organic disease of multiple organ systems. EEG recordings can also aid doctors in differentiation between organic and non-organic symptomatology.

Brain disease can have a variety of causes, known as encephalopathy. Encephalopathy is an inflammation of the brain that causes disruption in how the brain cells communicate with each other or the body.

EEG can also be done in other conditions such as stroke, sleep conditions, multiple types of seizures or convulsions that is not epilepsy, amnesia, and cerebral palsy

An EEG also might be helpful for diagnosing or treating neurological development of the brain in neonates, infants, children and degenerative brain dysfunction in all age groups.

 

ICU Continuous Electroencephalography (cEEG):  

In patients with impaired consciousness EEG is the only method of differentiation between non-convulsive status epilepticus or encephalopathic causes of suppressed brain function. 

An EEG also might be used to confirm brain death in someone in a coma. A continuous EEG is used to help find the right level of anesthesia or sedation for someone in a medically induced coma.

After identification of status epilepticus on routine EEG evaluation, cEEG is used to evaluate treatment efficacy and monitor the brain for continued subclinical abnormal activity or medically necessary therapeutic brain activity suppression during general intravenous anesthetic administration.

cEEG is required until a patient regains consciousness and may take several days.

Long-Term Electroencephalography (Long-term epilepsy monitoring LTEM):   

Differentiating between organic and non-organic epileptic and non-epileptic seizures cases require long-term scalp EEG recording for finalization and formulation of an accurate and complete diagnosis.

Correct differential diagnosis is crucial for correct management and clinical differentiation can be impossible in many cases without EEG monitoring

Localization and diagnosis of epileptic types and identification of non-epileptic disorders through long-term EEG monitoring is essential for correct medical management of disease or referral to the correct department for further investigation.

Long-Term EEG monitoring may be as short as one night in the hospital or several days in an advanced specialised EEG clinic.