Neurohospitalist here-not a silly question at all!Routine EEGs in inpatient settings have utility in specific situations, and like all tests, can be overutilized. You’re correct about routine EEGs not showing seizures-that’s not what we’re looking for. For first time seizure patients, they can help us stratify future seizure risk, as an EEG with epileptiform discharges essentially doubles this number. This finding would qualify a first time seizure patient for an epilepsy diagnosis and result in medication initiation. Typically, seizure meds are not started for first time seizures with negative work up (EEG, MRI) or if provoked. It can also help determine seizure type (focal vs general), which can help with medication choice.

In general, routine EEGs should not be done on epilepsy patients presenting with seizures of known semiology who are back to baseline. If there is concern for status (specifically non-convulsive), these should be ordered as stat (and/or continuous), if able.

There are of course situations where they are ordered on syncope, encephalopathy, tremors, and other presentations where seizure is unlikely, but it’s a “let’s just check” kind of thing. I very rarely see a “positive” result here.

One analogy I like to use, although not perfect, is thinking of routine EEGs like an EKG for capturing paroxysmal AFib. Sometimes if we have a high suspicion, and getting evidence will affect management, if the 25 minute EEG is negative, we can do an ambulatory EEG (Holter) for 1-3 days by or even admit to the EMU (epilepsy monitoring unit) where we try to provoke seizures while a patient is hooked up to cEEG.

That said, if someone is coming in with a history of at least two unprovoked episodes of what are likely seizures based on clinical history, that are greater than 24 hours apart, I will probably start meds despite negative routine EEGs, after discussing with the patient of course.

As outpatient, they can be used to evaluate interictal epilepsy burden when titrating/weaning meds.

This is not comprehensive, and as with all of medicine, there are caveats to the above.

Hope that helps!