Micro-strokes mimic Alzheimer’s Disease

SAN DIEGO — In the mid-20th century, senior citizens suffering from hopelessly muddled thinking were generally described as having hardening of the arteries. Today, they are characterized as having Alzheimer’s disease. But a new study suggests the disease accounts for only about half the cases of dementia. Many instead trace to a previously unappreciated source: microscopic losses of blood flow in the brain.