Hyperventilation during an EEG

I recently had a sleep/awake EEG. I know that they sometimes use photic stimulation or hyperventilation to enduce epileptiform features, but I wanted to know which brain waves specifically are affected (and what are the normal changes that should occur) during hyperventilation during an EEG? And what types of changes would be considered abnormal?

[Lori707]

I just had and EEG this week. The first thing they had me do is to hyperventilate. Within a minute, my body turned so cold and I had twitches all through and my teeth were chattering. But the shakes and teeth chattering were not from the cold. It took me some time to calm down. My husband was in the room with me and asked the tech if he saw something wrong. Of course the tech can't say, only your doctor, but from what he did say, it seems that the test was negative. If it is negative, then why would I go through an epidsode?