I tried on Bryan Johnson's brain helmet — it's a futuristic Apple Watch for your noggin

Kernel's Flow headset was designed by a former Oakley employee. I can see the resemblance to a fancy ski helmet. Maggie Shannon for BI I'm sitting in a small, dark room with my head wedged inside a very heavy helmet. It's surprisingly comfortable, considering its 5.5-pound weight, with dozens of plastic circles that look like little bedazzled lightbulb sockets gently burrowing through my hair and onto my scalp. Here I am, ready to measure my brain fitness. I'm taking two exams at the brain-m...