I am also 85 with PD in addition to severe lumbar stenosis and a bone on bone knee scheduled for a partial replacement. I had a TKR on left knee 12 years ago. PD is absolutely NO fun. Getting so many "symptoms" I don't know which I hate worse. Whenever something else happens I check and sure enough Parkinson can cause or be a factor. First thing even before I was diagnosed I was living in a Senior Facility with 3 meals a day, yet I lost 20+ pounds in about a year. So first thing I discovered is PD can cause weight loss. Now I have more sleep problems (never had before) , constant mucus/phlegm going through boxes of tissue, scaly skin like dandruff on my head and forehead and behind my ears, coughing a lot, CONSTAPATION, stiffness, a little trouble swallowing occasionally. But with my backpain and knee pain, I tend to ignore these. Because pain meds, stenosis and PD can all cause constipation, I can't ignore that. There are over 40 symptoms' for PD. Usually starts with tremors, usually with one arm/hand.
I have gotten help from the Parkinson's Foundation, from various clinics online, from the UK. Initially when I signed up with Michael J Fox Foundation the first 3 emails I received were for plea for donations, bur since then I have attended online webinars and discussions which are helpful. The Parkinson's foundation gave me he names of local doctors specializing in PD. DIET, Yes there is a PD diet, but they also recommended the Mediterranean diet. There is a Parkinson's Protocol which is non medical, but eating all the right foods. There are list foods that provide dopamine, which is what you brain is missing and caused by PD.
Wish you all the best with the PD challenges.
Gary Matthews NC