I think when you have an electric shock, the electric current travels through your body to a point where they can be earthed. The extent to which any physical injury occurs is correlated with the amount of current that this person was exposed to.
Paralysis, as i understand it, of any body part results from injury or malfunction of the brain part that controls that body part eg if you have a blood clot that travels to the brain and blocks blood supply to part of the brain controlling speech, the brain cells at this part will die resulting in speech paralysis. Similar scenarios can happen in cases of burst blood vessels in hypertensive patients, after an accident or even infection with some parasites or worms. I do not know whether an electric shock can result in paralysis. But if it can cause a physical injury in the brain, maybe