I have found one meta-analysis which shows that it can be beneficial for already active independent elderly, though the improvement appears small. If I read the stats correctly, for the mobility impaired or in need of care elderly, it seems to very slightly dimish their results, though the article concludes it has the potential to positively influence dynamic balance. To me, having the potential to do something and actually achieving positive results are two quite different things.
As discussed on this forum in relation to massage chairs, perhaps the best bet is to consult a physiotherapist who can work out an excercise regime specifially tailored to what is needed.
