The world's oldest woman, Edna Parker, died Wednesday in Shelbyville, Indiana. She was 115 years old. Parker, a former Indiana schoolteacher, was one of the 15 longest lived people ever.

A Dutch woman who reached 115 years of age and remained mentally sharp throughout life had a healthy brain when she died. The new study suggests Alzheimer's disease and other forms of dementia are not inevitable, as had been suspected.