Fatigue is one of the most common symptoms of MS, and may be the most prominent symptom in a person who otherwise has minimal activity limitations. Joseph Berger, MD, and colleagues (University of Kentucky, Lexington) looked at the frequency with which fatigue “heralds” the onset of MS. Among 5305 people with MS, 29% reported fatigue in the three years before MS diagnosis. In 30% of these patients, fatigue was the only symptom preceding MS diagnosis. Fatigue preceded MS diagnosis by an average of 501 days. The authors advise that, in people experiencing unexplained fatigue, a detailed neurologic history and exam should be conducted to rule out MS.