I spent two weeks in a hospital a few years back which had a specialized Parkinsons section.
They had a team of different para medical staff who treated PWP exclusively and so were very knowledgeable about it.
The physiotherapist during her session with me got me to close my eyes while she stood (ready to catch me luckily) as I would have fallen otherwise.
She gave me a lecture on the perils of that and I've noticed since too if for instance I'm in the shower and close my eyes for a moment I now know to hold onto the railing or risk a fractured femur!
I guess it's a parkinson thing.
Cheers,
Lee