There are probably sights, smells, and surfaces you’d rather not experience related to your own body. It turns out there are sounds that people would rather not hear as well. That point was made quite clear to research engineers at the Georgia Institute of Technology who are developing a knee band with microphones and vibration sensors to listen to joints in motion.
The point of their research, which is funded by the Defense Advanced Research Projects Agency (DARPA), is develop tools to help orthopedic specialists assess damage and track recovery after an injury. Georgia Tech scientist Omer Inan is a three-time NCAA All-American at Stanford University and the school record holder in discus throwing. He had personal experience with bad knees and the sounds they make. When DARPA put out a call for wearable health tech to aid rehabilitation, Inan saw a chance to work on something that mattered to himself personally but to many others as well. So he submitted a project plan and it was accepted.
Inan and his associates have developed a device with flat piezoelectric film microphones that are placed directly on the skin. The microphones record sounds not from the air, but from the vibrations on the surface of the skin. They collect data on the sounds of movement, knees particularly, so that orthopedic healthcare professionals can later use the data to identify healthy and damaged processes in the knee and thus track rehab progress.
Apparently the sounds of knees in motion aren’t all that appealing. Surely you’ve heard your own joints cracking. Imagine that amplified. Inan’s first reaction to the sounds of knees cracking and grinding was one of delight. “It was a lot louder than expected and a lot clearer,” he said. Others didn’t have the same positive reaction, “It’s a little bit like some kind of Halloween stuff happening. You’re listening to your bones rubbing on each other, or maybe cartilage,” Inan said. A common reaction was, “Gross!”
As the data collects and the body of knowledge to interpret crunchy knee sounds grows, what sounds gross to you may be music to your orthopedist’s ears.