Let's start with the set up. As a Registered EEG tech or any experienced technician will tell you, Neonatal EEG's can be a challenging set up. At first glance you might think "bald, tiny head and less electrodes. I'm in!"
Although most EEG technicians can agree that bald is beautiful; neonatal EEG set ups have their own challenges. While we do use a reduced montage (double distance) not many people know why. It's simple. The brain hasn't developed all of its folds (depending on age- we will get to that in a minute) and the real-estate on a head 36 cm or less is quite limited even with smaller electrodes. Some labs have 5mm electrodes special just for these precious little ones. Even so, space is limited and we do not want to cause a salt bridge!
Pictured above is an example of a double distance set up. However we are missing some key electrodes in this picture.
Eye leads: Placed bilaterally on the outer canthus of the eye. Neonates require eye leads to detect seizure behavior in the eye movement (rhythmic nystagmus)
Chin leads: Placed bilaterally under the bottom lip just under those cute chubby cheeks to detect muscle movements and glossal kinetic rhythmic movements like tongue jutting, which does present differently than a sucking artifact.
Belly belts or naval leads: Placed bilaterally on either side of the umbilicus (or some labs use a belly belt with a monitor that goes around the baby's belly-just like it sounds) in order to detect apneas or breathing abnormalities. This also helps with clinical correlations based on witnessed behaviors or EEG findings.
EKG leads: Placed bilaterally on the chest below the clavicle to monitor heart rhythm
Age is just a number, or is it? Neonatal EEG interpretation is based primarily on age so we need to speak the language (EEG does have a language of its own!) to know what to look for on the EEG. Neonatal brains can change weekly, and what is normal for one age may be abnormal for another age. Confused yet?
PMA: The Gestational age+ chronological age= Post menstrual age (PMA)
Conceptual Age: The age from conception which is based off of mom's last menstrual cycle.
Chronological Age: This is the age from birth
Gestational age: Length of pregnancy
Here is a great example of a time chart for Neonatal EEG. https://www.learningeeg.com/neonatal
This chart can help you keep track of patterns and age for normal versus abnormal.
If you are brushing up on your neonatal skills or studying for your boards, this a great website with fantastic resources to help. Be sure to check out the ACNS Guidelines for additional help! https://journals.lww.com/clinicalneurophys/Fulltext/2016/08000/American_Clinical_Neurophysiology_Society.7.aspx
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