My mom gets these scary attacks suddenly and nobody seems to know what they are or the cause. It starts with a pain in the upper arm/shoulder and goes down her arm. Then she gets a sudden severe weakness on her right side of the body (mostly her limbs). She can barely move her right side and she begins to pretty much drag her leg and the rest of her right side. She pretty much collapses and goes to bed to sleep when that happens. When she wakes up the next day, she is better and it’s as if nothing ever happened. What could this be?