Alan Schein Photography/Corbis

Journalist Brian Williams hosts The Lincoln Awards: A Concert For Veterans & The Military Family on Jan. 7 at John F. Kennedy Center for the Performing Arts in Washington. Recent reports suggest the suspended NBC anchor may have embellished several of his stories. Paul Morigi/Getty Images Entertainment hide caption

itoggle caption Paul Morigi/Getty Images Entertainment

When combined with results of other neurological tests, and in the context of a thorough medical history, atrophy of the brain (shown here in an MRI scan) sometimes indicates Alzheimer's. Simon Fraser/Science Source hide caption

itoggle caption Simon Fraser/Science Source