When he was 59 years old, Greg O'Brien was diagnosed with early-onset Alzheimer's disease. Five years later, he is speaking publicly about his experience, even as his symptoms worsen.
Courtesy of Greg O'Brien
Actor and Alzheimer's advocate Seth Rogen testifies before the Senate Committee on Appropriations about the disease's damaging effects on patients and their loved ones.
Mandel Ngan/AFP/Getty Images
An Indian schoolgirl dressed as Telugu Talli poses for the camera during a celebration in Hyderabad, home to a study that seems to show the onset of dementia is delayed for people who speak more than one language.
Noah Seelam/AFP/Getty Images