Twisting branches, red fruit punctured by worms “nah-nah”ing you from inside your brain. The response: an expert nodding sagely, “All you have to do is meditate mindfully, and you’ll be better.” You close your eyes in obedience, and a worm plops on your cheek. This expert is no Sherlock Holmes. You want detecting and investigating brain injury — an “Ah-ha!” moment. So let’s begin detecting and ask: What is brain injury?