Progressive supranuclear palsy (PSP) is a rare neurological disorder that affects body movements, walking and balance, and eye movements. PSP is caused by damage to nerve cells in areas of the brain that control thinking and body movements. It is one of a family of neurological conditions called atypical parkinsonism and belongs to the category of frontotemporal disorders.

PSP is different from Parkinson's disease, although some of their symptoms are similar. PSP typically begins in a person’s mid- to late-60s, later than when Parkinson’s disease symptoms typically develop. The disease usually worsens rapidly and most people with PSP develop severe disability within three to five years of symptom onset. PSP can lead to serious complications such as pneumonia, choking, or head injuries from falls.

https://www.ninds.nih.gov/health-information/di...

Check this article
https://www.mayoclinic.org/diseases-conditions/...

Can you give us some context? PWP is person with Parkinsons normally...but I don't recognise PSP.