A new way of measuring the pressure inside your skull using simple sound waves from headphones was developed by space research.
The device is an effective early-warning system for patients recovering from head injury or brain surgery.
Just like blood pressure, our bodies control the fluid pressure around the brain to cushion it from hitting the skull.
Astronauts rely on their body's pressure control system to regulate fluid build-up in orbit, so space agencies are keen to understand how it works and adapts to weightlessness.
Monitoring 'intracranial pressure' is not straightforward - there are many techniques but they are cumbersome, invasive and require professional operation.