Try pilates which would be considered low impact. Can you go for slow walks?
Depending on other factors that may or may not make it appropriate, horsemanship and horseback riding is actually better excercise than you might think, and requires and improves balance, coordination and fine motor skills.
Would water aerobics be for you? A friend of my sister's found a place near her house that offers it, and she loves it.
I dont know if this will help but I got a Giselle. It's a glider. I have a herniated in c5-c6 so I cant use my arms but it really is pretty smooth. It's effective in getting your heart rate up a little and you're in complete control of your speed so it's something that could help you. The other thing that I have is the AB Lounger (are you seeing a patern here) neither of these things jar you or cause you to put stress on your joints. I really pray for you and hope that at least one of these idea helps you. When I first hurt my back I had a doctor tell me that I would be in pain forever and I got so depressed that I laid on the couch for years, I gained 70 lbs and let myself go. I finally began having epidurals and they have me to a point that I can do some aerobic excersize though I hurt at the moment. God Bless you.
I designed exercises to focus around full-range movement at the head, hands and feet -- in which the movement at those axes to the extremes, produces the greatest muscle contraction possible -- throughout the musculature of the body.
The whole neuromuscular system is designed to produce fine motor control at the hands, feet and head -- where most of the muscles are located, enabling all those movements. The major(larger) muscles mostly serve as support and movement is a secondary function.
For example, in playing basketball, most people are aware of the impressive gross movements but it is the fine movements of the wrists and fingers that determine whether the ball goes in or not. Record home run hitter, Hank Aaron used to say that it was "all in his wrists" -- his ability to turn (rotate)his wrists.
The great performers like dancers, gymnasts, ice skaters, are set apart by the extension (movement) at the hands, head and feet. These athletes are distinguished by extraordinary neck muscle development, along with young looking hands and feet beyond the usual occurrence.
The most shocking thing when visiting people of advanced dementias is that they never move their head at all -- and rather look like living statues. Despite the fact that a lot of people get a lot of movement activities, few people think to focus movement at those most critical areas of the body -- that are the major means of expression of the body and imply functioning in all the rest. If I send a directive to move the hand, it has to go through the rest of the neuromuscular structures to get out there -- obviously.
One of the markers of decreasing strength is the measurement of grip; as people lose foot strength, balance becomes a problem. All the exercise devices ignore these areas of the body because they don't require apparatus to activate. It is just a function of range of movement -- which most people overlook or forget they even have.
You make a fist, and then slowly and deliberately move that fist palmward as far as possible, attempting to increase that range of motion with each subsequent repetition. You'll note that the farther you move into that extreme range of movement, the more it activates the supporting muscles of the body. That contraction is pushing the residual fluids of the tissues (bloat) back to the body, so that there is space for the heart to pump the new fluids into that area, optimizing the circulatory effect.
All these movements can be done without bearing any weight at all because the only measure is the range of movement -- that produces the maximum contraction. When you can effect the fullest range of muscular contraction alternated with the fullest range of relaxation, you have essentially trained your entire voluntary muscular system to aid the heart in optimzing circulation in the body -- which is the healthful effect.
You can check my profile for further writings on the topic.
Is there a place near you that offers Hydrobics (water aerobics). Since you're in the water, even with jumping, there is negligible impact, but if you get a good instructor, you WILL get a good workout! If there is a 'Y' near you, check that out. Some colleges also offer classes to the community.
Saw your profile. My son's best friend (20 years old) has Chiari and MS. Doctor said he had 10 good years left. Sad.