Brain's blood flow could change how we understand and treat Alzheimer's

Fifteen years ago, Marmarelis made a serendipitous observation: Alzheimer's patients show impaired vasomotor reactivity. "They cannot dilate the cerebral vessels to bring more blood in and provide adequate blood perfusion to the brain. This means they don't get the oxygen, nutrients and glucose that we need for cognition in a timely manner," he said. In their new study, Marmarelis's team tested this observation, developing a novel "physio-marker" called the Cerebrovascular Dynamics Index (CDI). This noninvasive test uses noninvasive Doppler ultrasound to measure blood flow velocity in some main arteries of the brain, and near-infrared spectroscopy to measure oxygenation in the...