Patient is in early 70s, female, very healthy, but has a slight thyroid deficiency issue that is adequately treated with the relevant drugs. Now, she occasionally (rarely) mentions that she experiences during the night very strong earthquake sensations. The experience feels to her 100% real, and is really frightening. She feels her bed shaking, etc... She is typically asleep. And, the event wakes her up in a state of anxiety. But, no earthquake has occurred. What could it be? What should she investigate with her health care providers?