House Speaker Nancy Pelosi (D-CA) signs the Education, Jobs and Medicaid Assistance Act at the U.S. Capitol,  August 10, 2010. Alex Wong/Getty Images North America hide caption

itoggle caption Alex Wong/Getty Images North America

Voice blindness, or phonagnosia, is a rare disorder that has to do with how the brain processes voices. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Tom DeBaggio, a herb and gardening expert, was diagnosed with early onset Alzheimer's disease in 1999. 1999 File photo/Washington Post via Getty Images hide caption

itoggle caption 1999 File photo/Washington Post via Getty Images