A 50-year-old woman is admitted with chief complaints of headache and decreased range of motion in her neck. She also complains of vertigo, hearing loss in one ear, profuse sweating, and uncontrollable eye movements. Her past medical history indicates that she was in a motor vehicle accident three days before her admission.

What are the possible causes of these symptoms?
What specific diagnostic testing would you recommend? Why?
What conditions should be ruled out? Why?
How would you distinguish between these conditions?