Hi,
I have also seen a few of these people. Panic attack is exactly the right word. This behaviour is often caused by symptoms of neurological diseases, like severe lack of visuo-spatial awareness and proprioception, which might have occured after an otherwise unnoticed stroke, but could also be due to emotional trauma or comes from being in bed for too long.MRI/ CT is a good diagnostic tool.
We used to hoist them, rather than manually transfer/ mobilise them and sat them out in a tilt 'n space wheelchair. Start with 10 min periods (e.g. when changing the bedding) and slowly increase every 3 days. Good team work by the helpers, positive encouragement, heaps of praise and perceverance is the key.
That's not based on evidence based practise or any formalised guideline ... - .. just personal experience.
Good luck,
Fyzzio