Dementia has become a catch-all term for certain diseases affecting the memory of tens of millions of people. The World Health Organization says over 55 million people have dementia worldwide, and it’s a leading cause of death among the elderly. A study published yesterday in the online journal Nature Mental Health found that it might be possible to detect dementia early and within minutes using a brain scan and machine learning. The World’s host Carolyn Beeler spoke to Charles Marshall, the lead researcher of the new study. He’s a neurologist at the Queen Mary University of London.