Six years after he was diagnosed with early onset Alzheimer's disease, Greg O'Brien is thinking differently about the future. Even as he fights to hold on to his memory, he and his wife, Mary Catherine, are discussing how to let go. Courtesy of Greg O'Brien hide caption
Greg unwinds a hose while doing some yardwork. Along with his failing memory, Greg has been experiencing secondary symptoms including paranoia, depression and slow healing. Amanda Kowalski for NPR hide caption
Writer Greg O'Brien and his daughter, Colleen, play with Adeline, Greg's 8-month-old granddaughter. Eight years ago, Greg was diagnosed with Alzheimer's disease. Meredith Rizzo/NPR hide caption
"My brain used to be my best friend," says Greg O'Brien, a journalist with early onset Alzheimer's. But he can't trust it anymore, he says. Alzheimer's is, in some ways, changing who he is. Amanda Kowalski and Samantha Broun for NPR hide caption
Despite losing his sense of taste and smell to Alzheimer's disease, Greg O'Brien says grilling supper on the back deck with his son on a summer evening is still fun. Sam Broun/Courtesy of Greg O'Brien hide caption
Greg O'Brien and his wife are finding it more difficult to drive to and from their family's secluded house on Cape Cod. As they move out and move on, O'Brien has discovered a bittersweet trove of memories. Sam Broun/Courtesy of Greg O'Brien hide caption
Greg and Mary Catherine O'Brien with their kids, at daughter Colleen's marriage to Matt Everett last August. Greg has early-onset Alzheimer's. From left, Brendan O'Brien, Greg O'Brien, Colleen O'Brien, Matt Everett, Mary Catherine O'Brien, and Conor O'Brien. Courtesy of Greg O'Brien hide caption
Greg O'Brien gathers his thoughts before a run in 2013. "Running is essential," he says. Michael Strong/Living With Alzheimers hide caption
Greg O'Brien (left), with Colleen, Mary Catherine, Conor, and Brendan O'Brien, has been grappling with Alzheimer's disease for the last five years. Courtesy Greg O'Brien hide caption
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 hide caption