Y: Stop that Don...why'd you put that microphone right next to my ear?
D: I was trying to record your otoacoustic emissions.
Y: My oto..what emissions?
D: Your otoacoustic emissions. Noises that your ears generate and emit.
Y: You mean my ear gives off noises?
D: That's exactly right. When you hear a tone or noise, the noise waves are transmitted to a part of your inner ear called the cochlea. These noises stimulate hair cells in the inner part of the cochlea that send electrical signals to your brain to be processed. Other hair cells in the cochlea are also stimulated, and these generate waves along the membrane of the cochlea that help to amplify and fine-tune the sounds you heard. These waves also get sent back out of your ear and can be heard if you amplify them.
Y: Wow, that's pretty cool Don. So you're telling me that my ear can talk to you?
D: In a way, it can. These noises tell about the functioning of your cochlea. Audiologists use these otoacoustic emissions to see if you have damage to certain portions of your cochlea that could keep you from hearing certain frequencies, or pitches of sound.Y: I always thought my ear was just a one-way street for noises to be interpreted in my brain. I never knew my ear could provide so much information about itself without my brain being involved at all.