Are there any definitive tests nowadays to confirm parkinsons. My dad is 84 and has Parkinson's for 18 years. I feel he may have been misdiagnosed way back then. But if he was and really didn't have it I'm sure the meds have taken their toll. He only has a slight tremor in his hand for 15 of the years. He did have a bad fall 3 years ago and has not been able to walk since. His legs are very strong but he just has zero balance. He's also declined cognitive wise a lot since the fall. Thanks