This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S., Subject name: Medicine
[{'content': 'A 47-year-old man presents to the emergency room with symptoms of dizziness and difficulty walking. He describes his dizziness as a spinning sensation of the room with associated nausea and vomiting. Which of the following findings suggests the vertigo is peripheral in origin? \nSelect and explain. \nA. optic neuritis, B. tinnitus, C. bidirectional nystagmus, D. vertical nystagmus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Tinnitus and deafness may be found in peripheral vertigo, but not central. The nystagmus is usually unidirectional and is never vertical. Visual fixation inhibits vertigo and nystagmus during testing in peripheral vertigo.', 'role': 'assistant'}]