Ellen Crimmell has kindly given me permission to post her video of her rescue oldie Chester, who has SM and has a full range of symptoms. This is an excellent video as she narrates it and explains what he is doing.
I also have further links on the SM website -- to pics and an explanation about the video on her website and an explanation by her neurologist on this site:
Note: Though Chester is clearly uncomfortable with aspects of his SM he is not in severe pain and this is very watchable and informative. In particular you can see the distinct sort of scratching and headrubbing he does -- symptoms many people have a hard time distinguishing from nomal behaviour.