In retrospect, Bernice Osborne realizes there were warning signs more than eight years ago.
Her mother, Mary, who was then 64, was having to re-read everything at her hospital job to grasp it. And she got lost one day going for a walk in their Dorchester neighborhood, where she had lived for 40 years.
Now nearly 73, Mary is in the throes of Alzheimer’s, unable to remember her own children, who care for her at home. With four aunts also diagnosed with the disease, Bernice, just 39, worries about her future.
“There are moments,’’ she said, “when you walk into a room and you forget what you were doing and you think, ‘Do I have it?’ ’’
Scientists think Alzheimer’s begins to damage the brain years before memory lapses and other symptoms appear, and they are developing screening tests to detect victims in these silent early stages. A reliable test would not only give people like Bernice an answer, but might enable physicians to prevent or delay the dementia with drugs or other therapies — much the same way patients with high cholesterol readings are treated with statins to stave off heart disease.