A few more answers for David. Forced exercise: Most people normally pedal at a cadence of 50-55. By pedaling at 80-90 rpm the person is either forcing herself or being forced to pedal at about half again their normal rate. The protocol for Pedaling for Parkinson's is three times per week, one hour each time (10 min warmup, 40 at cadence of 80-90 rpm and 10 min cool down) keeping the heart rate at 60-85% of maximum heart rate, (follow link to get heart rate). http://well.blogs.nytimes.com/2014/0...art-rate/?_r=0

You can do this at home, at the gym, in a Pedaling for Parkinson's class (offered at several YMCAs), on a stationary or spin bike. I put my road bike on a trainer in the winter and ride on the road when the weather permits. Benefits from the few tests that have been completed show a residual effect for four weeks. Dr. Alberts is not sure why this works but there appears to be some neuroregeneration happening. After seven years since diagnosis I am still at level 1 with my doctors shaking their heads. It's the cadence that counts, and consistency. No therapy will work the same for everyone, but there is nothing to lose and much to be potentially gained through this cycling program.