Parkinson's and age

Parkinson's and Age What is the difference between getting old and having Parkinson's? My 87 yr. old Mother-in-Law has much poorer balance, moves much more slowly, and is much less flexible than 65 yr. old me. Yet she's said to be OLD and I'm said to be a PWP. The only classical symptom where she comes off looking better than me is tremors, but I'm clearly trouncing her in three of the four most prevalent symptoms.