Progressive Supranuclear Palsy (PSP) is a rare brain disease in which small, pea-sized lesions form in the brain causing loss of balance, complex eye movements, blurred vision and progressive dementia. As the name indicates, the disorder is progressive and gets worse over time. Many of the symptoms mimic Parkinson's disease which makes it hard to diagnose.
Lynn's physical therapist asked if Lyn had been evaluated for it. She has not. He indicated that the symptoms he's seeing are similar. Regardless of the cause of her gait issues, the therapeutic approach is the same.
Mom placed a call into Lyn's physician to give her the name of the disease and to see if Lyn needs to be evaluated or if it can be ruled out. I've not noticed the eye movements described in the link above. I doubt that PSP is a factor here. Even if it was, according to the NIH, mortality is usually within 10 years of the onset of symptoms, often as a result of aspiration pneumonia. Aspiration pneumonia is also a risk with Alzheimer's. Neither have treatments available. So, even if it is PSP, she's got a progressive neurological disease.