What does xl event and xl spike mean on an eeg in a tbi patient?

This is event mark: This is likely an event mark from the eeg software by the brand xltek.

Automated marking: What you are seeing are signals that the automated spike detection software has flagged for further review by the neurologist. Unfortunately, while the software is extremely sensitive, it does have a high susceptibility to noise and artifact, and as such the markings you see are most likely normal. A neurologist can look at the raw tracings and tell you if they are truly concerning.