A miracle happened in 2009 on a cold January day when US Airways Flight 1549 made an emergency landing on New York City's Hudson River after a flock of geese caused both of its engines to lose power. Thanks to the quick thinking of Captain Chesley "Sully" Sullenberger, the plane landed safely, and all 155 people on board were saved. This week, the world learned of Capt. Sully's diagnosis of Alzheimer's disease, and Dan spoke with Tufts Medical Center's Dr. Brent Forester about this debilitating disease.