Could definitely be neurological looking at the video but a few other quick things to tick off would be mites - check on the back and neck at the base of the feather shafts in several places to see if they're present. They tend to congregate on the head or around the ears, causing shaking of the head.
If it's come on suddenly, could also be pin feathers aggravating her too.
That being said, it does look more neurological. Is she frail or uncoordinated on her feet?
I'd check the head over for bruising as well (green discoloration of skin), which may indicate an injury.
Honestly it looks like the MBD shakes reptiles get when they haven't gotten enough full spectrum UV, leading to calcium/vit D deficiency.
If she's always been this way and has rounded nutrition (ideally pellet or crumble, which ensures proper ratios are ingested), it could be something metabolic, causing issues with the uptake of nutrients.