Hi I am also looking for that same information. I would have thought that soneone or some Neurlogist would have made a study of this. I would think that it would be extremely valuable info. I requested this same info several weeks ago, but received only a few responses. Those people were all pretty positive after 1 -- 2 years. I did not hear about the failures. This is just as important. SO ANYONE OUT THERE THAT HAS THIS KIND OF INFO, PLEASE LET US KNOW. THANKS ALLAN