Caffeine & EEG

My son was sent for an EEG which came back normal. He was not told anything about not having any caffeine. His doctor has now sent him for a sleep deprived EEG and was told not to drink any caffeine. I'm curious....does the caffeine interfere with the actual test, or is it because they don't want it to keep you up during the test (I know they want him to sleep during the test).

The reason I ask is because we stayed up all night, and then without thinking he drank a beverage three hours prior to the test. We are having difficulty finding out if it had caffeine in it or not. The bottle did not say caffeine free, but did not say contains caffeine. He went for the test anyway - but, I'm wondering if the caffeine effects the actual test or not. He was able to fall sleep during the test.

Does anyone know for sure why caffeine is supposed to be restricted for this test?

Thank you for your response Darren! I called the manufacturer of the beverage (Fuze) and was told the bottle contained 22.5 milligrams of naturally provided caffeine. No additional caffeine was added. Knowing the quantity to be that small me feel better as well as reading your response.

I've had several of the sleep deprived EEG's done myself and I don't recall them ever telling me to refrain from caffeine.  I probably would not have stayed sleep deprived the next morning with out my Diet Coke to make the ride down to Vanderbilt.  I agree with Darren that he is most likely safe.  Be sure and keep us posted as to how he is doing.

Take care!

Carla