If your brain is swelling, either due to infection or physical injury, you're going to need these Headsense cranial monitors more than you need another hole in your head.
The fluids in your cranial cavity exerts a specific force on the brain and skull, known as your intracranial pressure (ICP), and help keep your brain from sloshing around in there. Sometimes, however, your ICP can rise due to a knock on the head or a disease like meningoencephalitis, causing the brain to squish against the skull and cut off blood flow to the afflicted regions (effectively causing you to stroke out)
Headsense is an Israeli startup that has developed a pair of disposable ear buds that monitor ICP using sound waves rather than drill bits. The buds will sound a series of low frequency tones on one side of your head and record the sounds as they pass through your skull to the other bud. By measuring the distortions to that tone caused by blood flow variations, the system can calculate your ICP in seconds. “It’s kind of like a pipe organ,” Weinberg says. “A pipe organ has pipes with different diameter that produce sounds with different pitch. This is exactly the same case.”