Firm developing early Alzheimer's test

It's a disease that causes progressive decline in memory and thinking skills, and behavior. Alzheimer's is a type of dementia, and although exact cause of the disease is not yet fully understood, scientists are striving to find an answer. Researchers in Scotland hope they're one step closer. Professor Craig Ritchie, founder and CEO of Scottish Brain Sciences, talks to Mark Leishman about a deal with a major pharmaceutical company to develop blood tests which could detect Alzheimer's disease in the very earliest stages.