Is It Normal Aging or Alzheimer's?

Some 46 million Americans already have the early brain changes that are the harbingers of a dementia that won't reveal itself for decades. Dr. Richard Isaacson, Director of the Alzheimer's Prevention Clinic at Weill Cornell Medicine, talks about the three stages of cognitive impairment, how to distinguish "senior moments" from symptoms of dementia, and whether multitasking puts our overloaded brains at risk.