How To Treat Involuntary Arm And Leg Shaking?

I am 56 yr old female, who for the past 7 years, at times upon risingto my feet from a sitting or lying position my arms and legs shake involuntarily for a brief period of time. I have to sit down or hold on to something or somebody, or I will fall down to the ground before it stops. Sometimes I can t control my bladder. I have been checked for MS, but a local Neurologist could not find the cause. I do not black out and arms and legs are the only part of my body that shakes. It is visible by other people, and it is a jerking not a tremor. I have a referral to have a complete neuro evaluation at Mayo in Jacksonville FL. What do you think? My carotids are clear and a cardiologist has completed a complete cardiac evaluation and he is the physician that has referred me for a complete neuro eval.