Is that where they need to be so they don't show on TV? I didn't watch the speech, but I don't recall seeing them on any of his previous speeches. It's all fake with him so having them not show is more important than having the wierd head tilt or his ridiculous head flap.
The screens are visible to everyone in attendance. They are out of the camera shot only if the camera choosed to go to a close-up of the speaker. I suggest that one reason for the elevated chin could be if he is reading down his nose as some bifocal or reading glasses wearers do. Since the media will not mention it we don’t know if he needs glasses, but most people his age do need them for reading.