May 8—As soon as Carolyn Perrygo noticed small signs that her husband John's memory was slipping back in 2010, they were sitting in a doctor's office, charting a path forward. Four years later, through a clinical trial, John Perrygo was diagnosed with Alzheimer's disease thanks to a positron emission tomography scan (PET) that wasn't yet available to the general public. The Perrygos are both .