When a baby fusses or cries, exhausted parents may wish they could know what's going on inside their baby's brain. Now, scientists hope clues could come with the help of a wearable brain imaging device. The new technology can track cognitive functions and may one day help identify early signs of autism or ADHD. ITV News science correspondent Martin Stew reports. PBS News is supported by - https://www.pbs.org/newshour/about/funders