Dizzy Dean, the great baseball pitcher of the 1930s-1940s, once quipped, "The doctors x-rayed my head and found nothing."

That is as good an analogy as any in describing what often happens to patients with the symptom of dizziness. They see a doctor, get an MRI scan (the x-ray of the 21st century) and nothing is found.

To extend the baseball theme, patients sometimes complete a triple-play