On a sunny spring day in 2009, Mary Ann Tosi was sitting in a Needham church, attending a memorial mass for her parents. As she sat with her family in a back pew, a pain crept up the back of her head.

KALAMAZOO, MI – Mix-matching numbers at work led Laurel Rosebush to the eye doctor in January. Instead of a pair of glasses, her doctor said she needed a CT scan. Rosebush, a 57-year-old Bridgman ...