My mum has just started going rigid whilst her arms stick out in front of her and shake. She actually slid off her armchair almost like in a cartoon. She was taken to hospital the first time and the doctor said it wasn't a seizure even though she watched it happening again. Does anyone have any experience of this? Mum is quite poorly now and has been peg fed for about a year, is incontinent and hardly speaks. Horrible, horrible illness.