In 1980 Alberca et al. described a patient with a syndrome of increased muscle irritability, who presented ondulating muscle rolling movements and electrically silent cramps, myoedema and muscle reactions to mechanical stimulation similar to myotonic response, suggesting a disfunction at myofibrillar level.
For c-3po, it was a costume, Anthony Daniels played c-3po: For R2-D2, It was a costume and a remote controlled robot. CGI was also used in the prequel trilogy. So, they had Kenny Baker to play him : And from Portrayal section of wookieepedia article on R2-D2 :
In addition, Holmes's faithful friend and companion Dr. Watson is portrayed as the kind of thoroughly competent sidekick that Holmes would want. Initially, Watson was portrayed by David Burke (who had earlier played the villain in an adaptation of The Adventure of the Beryl Coronet for the 1965 BBC series starring Douglas Wilmer and Nigel Stock).