Ok, the nerves follow a wiring diagram. The wires can be corroded (sick) or broken, but they are consistent. Corrosion works on the most exposed areas (the ends of the limbs are more sensitive; the ends of the extremities). This would be funny feelings in the fingertips and toes. Overall brain damage has overall effects. This is testable with formal testing or informal brain games (memory, pattern recognition, abstractions, interpretations of stories, speed of reflexes). Small effects in a young person are likely to get better. Rapidly. If someone is able to have a normal conversation, move everything, and generally have to have specific testing to find a problem (as opposed to not being able to speak, not remembering anything for more that a minute, not being able to move an entire side), then the damage cannot be major and is likely to resolve. Hand shaking can be an overall problem with coordination from brain damage. In which case the person falls over a lot, cannot dress themselves, etc. It can be from sick nerves in which case there is going to ALSO be sensation problems. Oh, this can happen from hyperventilation from breathing a bit much (or the ventilator not adjusted perfectly) and is temporary with recovery in hours to days or with electrolyte abnormality which continues to when you get a bit more magnesium and/or potassium into your system. Cannot say in this particular case without directly examining